By Bo Starr, Co-CEO of Grifin. Last verified August 17, 2026.

If $20 a month is the whole budget, the best app is a free one: Fidelity or Schwab, with an automatic $20 transfer into an index fund and $0 in fees. Any app with a monthly charge, including ours, takes too big a bite out of a deposit this size, and this post will show you the actual numbers instead of pretending otherwise.

Yes, "ours": Grifin is our app, and it charges a subscription. You'll see exactly where it does and doesn't make sense at this budget, with the math in the open.

Is investing $20 a month even worth doing?

Yes, and not as a consolation prize. $20 a month is $240 a year, and at roughly historical market returns, twenty years of it grows to somewhere in the neighborhood of $11,000 to $13,000 against $4,800 contributed. Real money, though the bigger payoff is behavioral: people who invest $20 a month reliably become people who invest $100 a month when the raise comes, because the account, the habit, and the identity already exist. The thing that kills small investors isn't the smallness. It's fees eating the smallness, which is why the rest of this post is mostly division.

How much do app fees actually eat at $20 a month?

Here's the arithmetic the roundups skip. Acorns Bronze costs $3 a month, which is 15% of a $20 deposit, every month, before your money earns anything. Acorns Gold at $12 would be 60%. Stash's single $12-a-month plan: also 60%. Betterment's $5 monthly fee for small accounts: 25%. Even a subscription in the single digits takes a dollar-for-dollar chunk that a $20 depositor can't laugh off, and that includes Grifin's flat single-digit monthly subscription. For scale, a $20-a-month investor at Fidelity pays $0 in platform fees and maybe $0.36 a year inside a cheap index fund. At this budget, fee avoidance is most of the strategy.

What's the actual best setup for a strict $20 budget?

Open a Fidelity or Schwab account (no minimums, no monthly fee), set an automatic transfer of $20 for the day after payday, and set it to buy a total-market index fund or S&P 500 index fund automatically; both brokerages support automatic investing into funds, and fractional shares mean all $20 goes to work. Turn on dividend reinvestment. Vanguard works just as well here; the point is the $0 platform fee, not the brand. And you can raise the transfer with every raise without touching anything else. That's the whole system, it takes fifteen minutes to build, and it beats every subscription app at this deposit size, ours included. If you want the money managed for you, Fidelity Go charges no advisory fee under $25,000, which keeps the total cost at effectively zero for years at this pace.

When does a subscription app make sense anyway?

In one situation: when the app changes how much actually gets invested. The comparison isn't "$20 minus fees at App A versus $20 minus fees at App B." It's "$20 that reliably happens" versus "$20 you meant to invest and often didn't." If a free account would sit empty, a paid app that produces deposits is worth real money despite the fee. That's Acorns' honest pitch, and it's ours too. The difference with Grifin is that the deposit isn't a fixed $20: it's driven by your everyday spending. Grifin members average around $18 per automatic deposit, and active members average about 67 automatic deposits a year, a spending-driven flow that typically ends the year well past what a fixed $20-a-month plan contributes. For spending-driven investing, the subscription is a smaller share of a bigger flow. If your true ceiling is $20 a month total, though, hear us clearly: don't pay us. The subscription is real money at this level, and Fidelity is the right call.

How does Grifin work, for the reader deciding between models?

The current mechanics, since older descriptions of our pricing model still circulate: Grifin links your bank accounts and cards through Plaid, reads your transactions, and automatically buys fractional shares of every publicly traded brand you spend at. It opens a real brokerage account, verifies your identity, funds by ACH, and places live fractional trades. There's no stock picking. More than half of our members had never invested before joining, and members who make three automatic deposits in their first 32 days keep their funded account at a 94 percent rate. It's built for the person whose problem was never the $20, it was the follow-through. If that's not your problem, the free path above keeps every dollar.

What should you do this week?

Decide which sentence is true about you. "If it's free and automatic, I'll let it run": open Fidelity or Schwab, automate $20 into an index fund, done, and revisit the amount every raise. "I've tried that and the account died": pick the paid app whose mechanic matches your life, round-ups at Acorns if spare change appeals, spend-linked ownership at Grifin if you'd rather your Target runs build Target shares, and treat the fee as the cost of the version of you that invests. Either way, the worst-performing app at any price is the one you research for another month. $20 invested this Friday beats a perfect decision in October.

Facts about other apps checked against their own pricing pages on August 17, 2026.