Every app advertises commission-free trading, so they must be identical, and picking one is a coin flip. Then someone discovers at 3am that their withdrawal takes four business days, or learns a “free” plan routes their orders to whoever pays the most for them. The commissions disappeared; the differences moved somewhere less visible.
What a broker actually does
You can’t walk onto an exchange and trade. Members-only access means a broker sits between you and the market, holding your cash and securities, executing orders, and reporting to tax authorities. That custody role matters more than the trading button: when something goes wrong, whether it’s a mistaken deposit or a frozen account, who you’re dealing with determines everything.
As a minor you can’t open one alone, which makes choosing partly a conversation with an adult rather than purely your decision. See Opening Your First Brokerage Account for custodial versus Custodial Roth mechanics and the financial-aid trap nobody mentions until applications are due.
Fees nobody puts in the headline
Commissions, near zero on US stocks now, genuinely. This part of the marketing isn’t misleading.
Payment for order flow. Some brokers route customer orders to market makers who pay for the privilege, then profit on the spread. Studies have compared execution quality across venues and found meaningful variation. It doesn’t make a platform illegal or evil, but “free” describes the fee schedule, not the whole economics of your trade. Compare against The Hidden Costs of Trading: Slippage, Spreads, and Market Impact.
Inactivity charges. Some platforms bill monthly if you don’t trade often. Trap for anyone investing small amounts slowly, which should be most beginners.
Fund minimums and expense ratios. A brokerage with zero commissions still lets you buy funds charging over 1% yearly, which quietly dwarfs any commission ever charged. The platform being free says nothing about what’s inside it.
Transfer-out fees. Moving your account elsewhere can cost money. Not urgent today, relevant eventually.
The things that matter more than the app interface
SIPC coverage. Protects you if the broker itself fails (not against losses on trades) up to statutory limits, typically half a million dollars including a cash sublimit. Every legitimate US broker has it, and confirming it takes about thirty seconds.
What else it holds. Retirement accounts, fractional shares, automatic recurring investing, index fund selection, and research tools vary widely. Recurring contributions matter disproportionately for someone investing $25 a week, since manual transfers create opportunities to stop or to panic-time.
Withdrawal friction. Delays aren’t fraud, but multi-day holds during urgency teach you what customer service is really worth. People learn this only when they need money fast.
Account type support. Custodial Roth IRAs require earned income, and several popular apps restrict account menus for under-eighteen users, sometimes pushing expensive actively managed products instead of cheap index funds because those earn more revenue per dollar. Be skeptical if the default recommendation costs more than obvious alternatives.
Do this today, fifteen minutes
Write down exactly three requirements. Something like: supports custodial account, no inactivity fee, allows $10 fractional purchases of an S&P 500 index fund. Then evaluate two candidates against your list rather than against vibes and friends’ screenshots.
Next, find each platform’s own disclosure page for payment for order flow and read it. Skim, don’t agonize. Purpose isn’t to decide it disqualifies them, most mainstream options are entirely reasonable, it’s building the reflex of checking disclosed incentives before trusting a free label. Finally locate their expense-ratio table for the cheapest broad index fund they offer and write the number next to the name.
That single digit likely affects your thirty-year outcome far more than which logo appears on your phone. For what to do once the account exists, follow Making Your First Trade and then Building Your First Portfolio.
Educational content, not financial advice. Platforms differ in ways advertising omits, and all investing involves risk, including loss of money.