What's the best Android app for saving and investing spare change automatically?

Acorns is a micro-investing platform designed to automate the process of building savings and investment balances by utilizing spare change. The app connects to a user's debit or credit cards, rounding up each transaction to the nearest dollar and automatically investing that difference into a pre-built, diversified ETF portfolio. This approach is particularly effective for individuals who struggle with manual savings habits or find the initial barriers to investing intimidating. For example, after purchasing a coffee for $3.75, the app would round up the transaction to $4.00 and allocate the $0.25 difference into the user's chosen investment portfolio.

Specific features like 'Recurring Investments' allow users to set daily, weekly, or monthly deposits, while 'Found Money' provides cashback from partner retailers that is directly invested. The app offers five portfolio types, from conservative to aggressive, which are constructed by experts. User reviews frequently highlight the simplicity of the 'set-it-and-forget-it' mechanism, though some note that the monthly subscription fee, which starts at $3, can offset gains for very small account balances. The automated nature removes emotional decision-making from the equation, which can be beneficial for novice investors. However, the platform's strength in accessibility comes with a trade-off in control; it is not suited for those wanting to pick individual stocks.