How to Start Investing with $100

One of the biggest myths about investing is that you need a lot of money to get started. I believed this for years. I figured I'd start investing "when I had more saved up" — which is a great way to never start at all.

The truth is, you can start with $100. Even less, actually. And while $100 won't make you rich, starting the habit of investing is worth more than the dollar amount.

Here's what I'd do if I were starting from scratch today with $100.

Why $100 Matters More Than You Think

Let's be honest — $100 invested isn't going to change your life overnight. But that's not the point.

The point is building the habit and breaking through the psychological barrier. Once you have money invested — even a small amount — you start paying attention. You check the app. You learn what a portfolio looks like. You stop thinking of investing as something "other people" do.

That mindset shift was worth way more to me than the actual returns on my first $100.

Option 1: A Robo-Advisor

This is what I did, and I still think it's the easiest path for most people. Open an account with Betterment (no minimum) or Wealthfront ($500 minimum, but you can start saving toward that), deposit your $100, and let the platform build a diversified portfolio for you.

Why this works: You get instant diversification across stocks and bonds without making any decisions. The platform handles rebalancing and, in some cases, tax-loss harvesting. You set it and move on with your life.

The trade-off: You'll pay a small fee (typically 0.25% annually). On $100, that's 25 cents a year — not exactly a dealbreaker, but it's worth knowing about as your balance grows.

Option 2: A Fractional Share Brokerage

Apps like Fidelity, Schwab, and Robinhood let you buy fractional shares — meaning you can invest in a single share of an S&P 500 index fund (or even individual stocks) for whatever amount you have.

Why this works: If you want more control over what you invest in — say, you want to buy into a specific index fund like VTI or VOO — fractional shares let you do that with any amount.

The trade-off: You're making the decisions. For some people, that's empowering. For others (me included, at the start), it's paralyzing. If you're the type to research for weeks and never pull the trigger, a robo-advisor removes that friction.

Option 3: Acorns (Round-Ups)

Acorns connects to your debit card and rounds up every purchase to the nearest dollar, investing the spare change. A $3.75 coffee becomes $4.00, and that $0.25 gets invested automatically.

Why this works: It's completely passive. You don't even think about it. Over time, those round-ups add up — I know people who've accumulated a few hundred dollars without noticing.

The trade-off: Acorns charges $3–5/month depending on the plan. On a small balance, that fee percentage is high. If you have $100 invested and you're paying $3/month, that's a 36% annual fee — way more than a robo-advisor. Acorns makes more sense once your balance is higher, or if you use the other features (retirement account, debit card, etc.).

What I'd Actually Do

If I had $100 and was starting from zero today:

1. Open a Betterment account (takes 15 minutes)
2. Deposit $100
3. Set up a $25/week automatic deposit — or whatever I could comfortably afford
4. Don't look at it obsessively (the daily ups and downs don't matter when you're investing for years)

That's it. No stock picking. No market timing. No waiting for the "right moment."

I'm not a financial advisor — this is what worked for me. Your situation might be different, and it's always worth talking to a professional if you're making big financial decisions. Past performance doesn't guarantee future results, and all investing involves risk.

The Real Takeaway

Starting with $100 isn't about the money. It's about proving to yourself that you can do this — that investing isn't only for people with six-figure salaries and finance degrees.

Once you start, growing from there is the easy part. The hard part is going from $0 to $1. Everything after that is momentum.

If you want to compare robo-advisor options in more detail, I wrote a full breakdown of Betterment and Wealthfront that covers fees, features, and who each one is best for.