It’s super easy.
All you have to do is collect 4 stamps;
1 – Stream a show on Prime Video.
2 – Listen to a song with Prime Music.
3 – Borrow an eBook on Prime reading.
4 – Make one Prime eligible purchase.
5 – Activate your Stampcard on the promo page and you will receive one stamp after you do each activity. Each stamp can take up to 48 hours to appear on your Stampcard.
Collect all 4 of the stamps by the deadline of July 13th and you will get a $10 credit that will be applied right to your account. Easy peasy!