Robinhood

Robinhood pioneered commission-free stock investing and lets you buy fractional shares for as little as one dollar, meaning you can own pieces of expensive stocks without needing thousands upfront. The app covers stocks, ETFs, options, and crypto, with real-time market data and a straightforward interface designed for beginners. No account minimum means a student with 50 dollars can start investing immediately.

This appeals to students ready to invest but intimidated by traditional brokers or lacking the capital for whole shares. If you want to dollar-cost average a small amount monthly or experiment with investing before you have real money, Robinhood removes every barrier. The downside is limited research tools and no traditional banking, but for pure investing simplicity and low entry cost, it's hard to beat for a 20-year-old starting to build wealth.