Monzo is basically a loadable debit card that can also do some savings account stuff. Once you add some funds to the Monzo card (which took about two days to arrive) and spend at least $5 on that card, Monzo will automatically give you $15 bucks. The only restriction is that the money needs to be spent on "real" goods, not gift cards or digital goods/in-app-purchases. I just added $10 and bought a latte at Starbucks (and the leftover money can be taken out again along with the $15).

Sign up and you'll get a free fractional stock share (worth at least $5)

Sign up with Venmo and send $5 to someone within the first two weeks, and Venmo will throw you another $5!