If you're new to Rakuten, you can get $40 deposited into your account for free simply by making at least $40 in purchases through their site within 90 days. You can make multiple purchases at multiple stores – you simply have to spend at least $40 total within 90 days. You'll then get paid $40 either by check or PayPal.
Rakuten is a cash-back shopping portal that pays you a rebate on purchases at thousands of online retailers. They pay you anywhere from 1% to 20% cashback on your purchases, depending on the store.
You can shop with hundreds of stores, like Target, Walmart, Disney, Best Buy, Kohl's, Old Navy, Petsmart, and literally 500+ more. Practically every store except Amazon is available for cash-back on Rakuten.