"I'll start investing when I have more money" is the sentence that keeps millions of people broke. Here's the truth: the best time to start investing is with whatever you have right now — even if it's $100.
This guide explains exactly where to put that $100, what to expect, and why starting small is actually one of the smartest financial moves you can make.
Why $100 Is Enough to Start
Twenty years ago, investing required thousands of dollars just to open an account and hundreds more in brokerage fees. Today, every major investing app has no account minimum, no trading fees, and lets you buy fractional shares — meaning you can invest $10 in a stock that costs $500 per share.
The barrier to investing is psychological now, not financial. You don't need a financial advisor or a lot of money. You need $100 and 20 minutes to set up an account.
What $100/month invested looks like over time (10% average annual return)
That table isn't magic — that's compounding. You contributed $36,000 and ended up with $226,000. The market did the rest. But only if you start.
Step 1: Build a $1,000 Emergency Fund First
Before you invest anything in the stock market, make sure you have at least $1,000 in a savings account as an emergency buffer. This isn't optional advice — it's necessary. If you invest $100 and then your car breaks down, you'll be forced to sell at a bad time. Your emergency fund keeps you from panic-selling.
If you don't have that yet, a high-yield savings account (HYSA) paying 4–5% interest is where your first $100 should go. It's not exciting, but it's the foundation everything else is built on.
Best HYSA options right now: SoFi, Marcus by Goldman Sachs, and Ally Bank consistently offer the best rates with no minimums and no fees. Check current rates — they change based on the Fed rate.
Step 2: Open a Roth IRA (Best for Most Beginners)
Roth IRA — The Best Account for Most People
A Roth IRA is the single best investment account for most beginners. You invest with after-tax money, so everything it earns grows tax-free. When you retire, you withdraw it all tax-free. Open one at Fidelity, Vanguard, or Charles Schwab — all have $0 minimums. Then put your $100 into a simple index fund (more on that below).
If your employer offers a 401(k) with a match, contribute enough to get the full match before anything else. A 100% match is an instant 100% return — nothing beats that.
Step 3: Put Your Money in Index Funds (Not Individual Stocks)
S&P 500 Index Fund (VOO, FXAIX, SPY)
When you buy an S&P 500 index fund, you're buying tiny pieces of 500 of the biggest companies in America — Apple, Microsoft, Amazon, Google, and 496 more. When the US economy grows, your investment grows with it. This is what Warren Buffett recommends for average investors, and it's what most financial experts agree on. It's boring. That's the point.
Avoid this: Don't put your first $100 into individual stocks, crypto, or options trading. Those require research, experience, and risk tolerance most beginners don't have. Build a foundation in index funds first. There's plenty of time to experiment later.
What Apps to Use
Fidelity (Best Overall)
Fidelity has no minimum, no fees, fractional shares, and some of the best index funds (FZROX has a 0% expense ratio — meaning they literally charge nothing). It's what most financial experts actually use themselves. Open a Roth IRA here and put your contributions into FZROX or FSKAX.
Acorns (Best If You're Bad at Saving)
Acorns automatically rounds up your debit card purchases and invests the difference. Buy a coffee for $3.40 and it invests $0.60. It's not the most efficient method (the $3/month fee is high relative to small balances), but it works for people who struggle to manually move money into investments. Once your balance hits $1,000+, consider moving to Fidelity.
The One Rule That Matters Most
Automate it. Set up a recurring transfer of whatever you can afford — even $25/month — into your investment account on payday. Automate your investments the same way your bills are automatic. When it's automatic, you don't have to make a decision every month, and you can't accidentally spend the money first.
Time in the market beats timing the market. The S&P 500 has historically recovered from every crash and continued to climb. The people who made the most money are the ones who never stopped contributing, even during scary downturns.
Your Starting Checklist
- Open a high-yield savings account and build a $1,000 emergency fund
- Open a Roth IRA at Fidelity (takes 10 minutes, $0 to start)
- Deposit your $100 and buy shares of FZROX or another S&P 500 index fund
- Set up a recurring monthly contribution, even if it's just $25
- Leave it alone and let it compound
That's it. Five steps. You're now doing more than 80% of Americans who never start at all.
Want more money to invest? Check out our guides on the best side hustles for beginners and how to make $100 fast — the more you earn on the side, the more you can put to work.
Disclaimer: This article is for informational purposes only and does not constitute financial advice. Always do your own research before making investment decisions. Past market performance does not guarantee future results.