Use APKPure App
Get Java QR old version APK for Android
Eat. Earn. Redeem. Repeat.
All you need to do is download the app, view the offers, and check the eligibility criteria (like which supermarkets are taking part). Once you've bought the product, scan the receipt (and sometimes the product's barcode), and voilà! You've got your cashback as a gift.
There are so many different coffee shop chains out there. And, there are loads of great ways to get freebies from them.