Rakuten is a cash back app and website that has paid out over $1 billion in cash back to consumers since 1999. (They launched under the name Ebates and changed to Rakuten recently when they were acquired).
I’ve personally earned almost $550 in cash back via their site since I signed up.
Whenever I’m about to make a big online purchase, like a DSLR camera for example, I’ll check a bunch of cash back sites via Cash Back Monitor, and quite often Rakuten has one of the best cash back percentages available.
Just start your shopping experience with their app (or on their site), and you’ll get cash back for your purchase once it clears.