You don't need thousands of dollars to start investing. I started with $100 — literally a single hundred-dollar bill transferred into a brokerage account on a Tuesday afternoon. Ten years later, that $100 is worth more than I expected, not because I picked the right stock, but because I kept adding to it and I didn't panic when the market dropped. Here's how to start with $100 and what I wish someone had told me a decade ago.
Most brokerages have no minimums and no commissions. You can buy fractional shares of ETFs and stocks for as little as $1. The barrier to entry isn't money — it's the decision to start. I waited years because I thought I needed $5,000 or $10,000 to "make it worth it." That was wrong. The $100 I invested at 25 is worth more than $500 I invested at 35, because it had 10 more years to grow.
The math is simple: $100 invested at age 25, earning 10% per year (the historical S&P 500 average), is worth about $4,500 at age 65. Add $50/month and it's worth about $350,000. The $100 matters less than the habit of adding to it.
Choose a brokerage with no minimums, no commissions, and fractional shares. The three I'd consider:
Open the account online — it takes about 10 minutes. You'll need your SSN, address, and employment info. They'll ask if you want a traditional IRA, Roth IRA, or taxable account. If you're not sure, start with a taxable account — you can always open an IRA later. See my Roth vs traditional IRA guide for help choosing.
With $100, don't overthink it. Buy a broad-market index fund or ETF. These are the simplest, cheapest, most reliable way to invest:
Don't buy individual stocks with your first $100. You don't know enough yet, and the fees (even if they're zero) aren't worth the risk of picking the wrong company. Buy the whole market with an index fund, and learn as you go.
With $100, you can buy fractional shares. Fidelity and Schwab both let you buy a dollar amount of an ETF, not just whole shares. So $100 in VTI gets you about 0.4 shares — and that's fine.
The $100 is the start, not the finish. Set up an automatic transfer — even $25/week — and invest it in the same index fund every time. Don't try to time the market. Don't check your balance every day. Just keep adding.
I set up an automatic transfer of $50 every other payday (about $100/month). I bought VTI every time, regardless of what the market was doing. Some months it was up, some months it was down. Over 10 years, it averaged about 10% per year. If you want to see how much your contributions could grow, my compound interest calculator shows the math.
What if the market crashes right after I invest? Good. You're buying more shares at a lower price. That's called a "sale." I lived through the 2020 crash — my portfolio dropped 30% in a month. I kept buying. It recovered within 6 months and was up 50% the next year. If you panic and sell, you lock in the loss. If you keep buying, you benefit from the recovery.
Should I pay off debt first? If you have high-interest debt (credit cards, 20%+ APR), pay that off first. The debt is costing you more than the market will earn you. If you have low-interest debt (student loans, mortgage), you can invest while paying it off. See my debt payoff guide for the order I'd tackle things.
What about my 401(k)? If your employer offers a 401(k) match, contribute enough to get the full match before investing in a brokerage account. That's a 100% return on your money — you can't beat that. After you get the match, open a brokerage account and invest there.
Do I need to talk to a financial advisor? Not with $100. A financial advisor costs $150–$300/hour or 1% of your assets per year. With $100, that's more than your investment. Buy an index fund, keep adding, and learn as you go. When you have $50,000+ or a complex situation (multiple income sources, business ownership, inheritance), then consider an advisor.
Starting with $100 isn't about the money — it's about the habit. Open a brokerage account, buy a broad-market index fund (VTI or VOO), set up automatic contributions, and don't check it every day. If you want to see how much your contributions could grow over time, my compound interest calculator shows the math. And if you're not sure where your money is going each month, my savings goal calculator helps you build a plan.
I started investing with $100 ten years ago. This site is one person writing about money — not a financial advisor, just what actually worked.