Buy your first $10.
The story so far Your Oakline account is open, and on Wednesday your $50 landed as buying power. You know what you want: an S&P 500 index fund. You search for it and see that one share costs about $700. You only want to put in $10 today. Good news: you can. You just have to tell the app exactly what to buy, how much, and at what price.
An order is your instruction to the broker: what to buy or sell, how much, and at what price.
The way you fill in the order decides what price you pay and whether the trade happens at all.
Look up the fund's ticker, choose dollars or shares, pick a market or limit order, check the numbers, and submit.
Market makers, firms like Citadel Securities and Virtu, stand ready to buy and sell all day. Exchanges like the NYSE and Nasdaq match buyers with sellers. Your broker sends your order to them.
What you're looking at: a sketch of a made-up order screen. The price is close to what one share of VOO really cost in October 2026. The circle stands for one share, and the green sliver is the part your $10 buys.
From a search box to a filled order.
Buying your first investment takes about a minute. Here's what each part of the order screen means, in the order you'll see it.
Find the fund by its ticker
Every stock and fund has a ticker symbol, a short code of letters you type into the search box. Names can look alike, so check the full name before you buy.
- Ticker symbol
- VOO is the Vanguard S&P 500 ETF. SPY and IVV are two other ETFs that copy the same index.
- Look-alikes
- VOOG holds only the faster-growing companies in the S&P 500, not all of them. VFIAX is Vanguard's S&P 500 mutual fund, which asks for $3,000 to start.
You don't need a whole share
The share price is what one share costs. Most big brokers let you buy a fractional share, a piece of one share, by typing a dollar amount instead of a number of shares. Your piece rises and falls by the same percent as a whole share.
- Share price
- One share of VOO cost about $700 in October 2026.
- Fractional share
- $10$700 ≈ 0.014286 shares, about 1.4% of one share. If VOO rises 10% to $770, your slice is worth $11.00, also 10% more.
Slide the amount and the price, then move the market, to see what you'd own.
What you're looking at: a calculator, not market data. The circle is one share at the price you picked, and the green slice is the part your money buys. Moving the price shows that your slice gains or loses the same percent as a whole share.
Fractional shares come with fine print. Some brokers only allow market orders for them, you usually can't move them to another broker without selling them first, and you may not get to vote at shareholder meetings.
The bid, the ask and the spread
A quote shows two prices. The bid is the most anyone will pay right now, and the ask is the least anyone will sell for. Buy right away and you pay the ask; sell right away and you get the bid. The gap between them is the spread, a small hidden cost on every round trip. Market makers earn it.
- Bid and ask
- VOO: bid $699.98, ask $700.00. You buy at $700.00. Someone selling right now gets $699.98.
- Spread
- $700.00 − $699.98 = 2 cents, tiny for a giant fund. A tiny company might show bid $4.00, ask $4.40: a 40-cent spread, about 9% of the price.
Market order or limit order?
A market order buys or sells right away at the best price available. It almost always fills, but the price isn't guaranteed. A limit order buys only at your price or lower, or sells only at your price or higher. The price is guaranteed, but it might never fill. Most limit orders are a day order: if they haven't filled by the close, they expire.
- Market order
- Buy $10 of VOO now: it fills in about a second at the $700.00 ask.
- Limit order
- Buy $10 of VOO with a $690 limit: it waits. If VOO falls to $690 before 4:00 p.m., it fills at $690 or less. If not, nothing happens.
- Day order
- VOO bottoms out at $694 today, so your $690 order expires at 4:00 p.m. Your $10 stays as cash.
When the market is open
U.S. stock exchanges keep market hours of 9:30 a.m. to 4:00 p.m. Eastern time, Monday to Friday, except holidays. Some brokers also trade in extended hours, before and after, when fewer people trade and spreads get wider. Orders sent while the market is closed wait for the open, and the price may be different by then. Many brokers only take dollar orders while the market is open.
- Market hours
- 9:30 a.m. Eastern is 6:30 a.m. in California and 8:30 a.m. in Chicago. The close, 4:00 p.m. Eastern, is 1:00 p.m. in California.
- Closed
- You send a market order for one whole share on Sunday night. It waits until Monday at 9:30 a.m. If VOO opens at $710, you pay about $710, not Friday's $700.
Pick a day and slide the time to see what happens to an order you send.
What you're looking at: a 24-hour band in New York time. Green is regular market hours, orange is extended hours at brokers that offer them, and gray is closed. Real exchanges also close on about ten holidays a year, which this sketch leaves out.
After you tap Submit
You get a trade confirmation showing the shares, price and total. The official handoff of cash and shares, called settlement, happens one business day later, a rule called T+1. Your app then tracks your cost basis, what you paid, next to your market value, what your shares are worth today.
- Trade confirmation
- "Bought 0.014286 VOO at $700.00. Total $10.00. Tuesday."
- Settlement
- Bought Tuesday, settles Wednesday. Sell on a Friday and it settles Monday, since weekends don't count.
- Cost basis
- $10.00, what you paid.
- Market value
- A month later VOO is at $735: 0.014286 × $735 = $10.50, a $0.50 gain.
Let it grow on its own
VOO pays dividends four times a year, recently about 1% of its price per year in total. Turn on dividend reinvestment and each payment buys more VOO for you. A recurring investment buys a set amount on a schedule, so you don't have to remember.
- Dividend reinvestment
- 1% of $10 is about 10 cents a year, so roughly 3 cents each quarter. Reinvested, those 3 cents buy about 0.00004 more shares.
- Recurring investment
- $10 every Friday is $520 a year going in without you lifting a finger.
Two minutes. Just listen.
Tap any line to jump to it.
Work the order desk.
Four missions on a practice order ticket, each at a different moment. Read the mission, fill in the ticket, and submit. If something's off, the app tells you what would really happen, and you can fix it. Your score counts the missions you get right on the first submit.
What you're looking at: a practice order ticket in a made-up app. VOO's prices are close to its real price in October 2026, but each day's ups and downs are made up, and so is Cobble Bikes. The chart shows the price during one trading day, from 9:30 a.m. to 4:00 p.m. Eastern.
The logic, step by step.
Four small calculations cover everything the order screen does with your money.
Step 1: How many shares your dollars buy
Divide the dollars you invest by the price of one share.
- $10 of VOO
- $10$700 ≈ 0.014286 shares.
- $10 with a $690 limit
- $10$690 ≈ 0.014493 shares. A lower price means a few more slivers for the same $10.
Step 2: What your slice is worth
Multiply your shares by today's price. Because your slice is a fixed piece of a share, it moves by the same percent as the share.
- VOO up 10%
- 0.014286 × $770 = $11.00. $11.00 − $10.00$10.00 = 10%, the same as $770 − $700$700 = 10% for a whole share.
Step 3: What the spread costs
Subtract the bid from the ask, then divide by the ask. That's roughly what you'd lose if you bought and sold right away.
- VOO
- $700.00 − $699.98$700.00 ≈ 0.003%. Almost nothing.
- A tiny company
- $4.40 − $4.00$4.40 ≈ 9.1%. Buy $10 and sell right away, and you'd get back about $9.09.
Step 4: Your gain or loss
Subtract your cost basis from the market value. Divide by the cost basis to get the percent.
- A month later
- 0.014286 × $735 = $10.50. $10.50 − $10.00 = $0.50, and $0.50$10.00 = 5%.
Worked example: your first order, start to finish
- Tuesday, 11:05 a.m. Eastern. Search VOO and check the full name: Vanguard S&P 500 ETF. Choose Buy, Dollars, $10, Market.
- One second later. Filled at the $700.00 ask: $10$700 ≈ 0.014286 shares. The confirmation says so.
- Wednesday. The trade settles (T+1). Buying power shows $40.00.
- End of the quarter. About 3 cents of dividends arrive and, with reinvestment on, buy a little more VOO.
- A month after buying. VOO is at $735: market value $10.50, cost basis $10.00, gain $0.50 or 5%.
Leaf-cutter ants carry it piece by piece.
A leaf-cutter ant can't carry a whole leaf, so it cuts out a piece it can carry and takes it home. Day after day, millions of ants in one colony bring back pieces, and the pieces feed a fungus garden that feeds the whole colony.
What you're looking at: an illustration, not data. Ants carry leaf pieces from the leaf on the left along a trail to their nest on the right.
Why this sticks. You don't need the whole $700 share. Take the piece you can afford, like $10, and keep bringing pieces home. A recurring $10 a week is the ant trail: small, steady, and it adds up.
The page you'd copy down.
- Order: what to buy or sell, how much, at what price. Ticker symbol: the fund's code, like VOO. Check the full name.
- Fractional share: a piece of a share, bought in dollars. Shares = dollarsshare price. It moves by the same percent as a whole share.
- Bid: what sellers get now. Ask: what buyers pay now. Spread: ask − bid, a hidden cost, tiny for big funds.
- Market order: fills now, price not guaranteed. Limit order: your price or better, might not fill. Day order: expires at the close.
- Market hours: 9:30 a.m. to 4:00 p.m. Eastern, Monday to Friday. Extended hours: before and after, with wider spreads.
- Settlement: one business day after the trade (T+1). Cost basis: what you paid. Market value: shares × price. Gain: value − cost basis.
- Dividend reinvestment and a recurring investment keep your money growing without extra effort.
Fill in the blanks
Grab a friend or a study group.
Ticker hunt
Each person finds three tickers for S&P 500 funds and one look-alike that isn't one. Swap lists and spot the impostor by reading the full names.
Limit-order bets
Pick a well-known stock. Everyone writes down a limit buy price for tomorrow. After the close, check the day's low to see whose order would have filled.
Slice math race
One person calls out a dollar amount and a share price, like $25 and $500. First to say the number of shares, 0.05, wins the round.
Just you and your money.
These stay on this device. Nobody else sees them.
Exam-style questions.
Written the way a college exam would ask them. Each right answer on the first try is worth 10 xp.
On the job: you're in customer support at a broker
A customer messages you, annoyed. On Monday morning she placed a limit order to buy VOO at $680 when it was trading at $695. That day VOO's lowest price was $684.10, and it closed at $690. Her order never filled and now it's gone. She thinks the app is broken.
Your task: explain in plain words why her order didn't fill and why it disappeared, then give her two ways to buy if she still wants to.
See a model answer
Why it didn't fill: a limit buy order only fills at your limit price or lower. Her limit was $680, and the lowest VOO traded all day was $684.10, which is still $4.10 above her limit. No seller was willing to go as low as $680, so the app correctly waited.
Why it disappeared: it was a day order, so it expired at the 4:00 p.m. close. Nothing was charged, and her cash is still in her account.
Her options: place a market order to buy right away at the current ask, around $690 if prices stay near the close, or place a new limit order at a price closer to where VOO is trading, like $688, knowing it still might not fill. If she's investing for years, a few dollars per share matter far less than getting invested.
From your first order to a lifetime of them.
What you're looking at: a map of where this lesson fits in the course. Read it left to right: the lessons that come before, this lesson in the middle, and the later lessons that build on it.
- Before · Unit 5Brokerage account
- Before · Unit 5Index funds
- You are hereYour first $10
- Next · Unit 5When the market drops
- Later · Unit 5401(k) and Roth IRA
- Later · Unit 10Percentages and growth