Over the past few years, a number of apps have popped up that help people save money. Each has its own bent, but at their core they offer the same service: collecting small amounts of money that add up over time. Here are five smartphone-friendly saving apps to help you easily set aside your spare change.

Acorns

Acorns invests your spare change in a basic investment portfolio. If you make a debit card purchase for $3.35, Acorns withdraws $0.65. It invests the money in $5 increments in one of five portfolio options ranging from aggressive to conservative, all with varying mixes of equity and bond exchange-traded funds. The app charges a $1 monthly service fee for accounts with less than $5,000.

Digit

Digit uses algorithms to analyze what goes in and out of your bank account, then makes small withdrawals in a way it says you "won't notice." Digit can save more than the other apps because it's not based on transactions but on your balance and spending habits. Digit charges $2.99 a month; you can try it free to 100 days.

Chime

Chime offers customers checking accounts, savings accounts and a debit card. Chime works with the Bancorp Bank, so your money is insured by the FDIC up to $250,000 per person per account. The Chime savings account carries a nominal interest rate. It doesn't charge a fee. It makes its money from debit-card transactions.

Clarity Money

Clarity Money, which is primarily a budgeting tool that identifies where you might be wasting money on things like forgotten subscriptions, partners with Acorns and offers its own savings app.

Long Game

Long Game is trying to redirect some of the money people spend on lottery tickets into savings by giving you a chance to win money by saving. It's called prize-linked savings, and the more you save, the more chances you have to win. Don't worry — the account is FDIC-insured, and you are not playing with your principal.