Walmart has a really neat offer. Buy 1 box of Ritz Crackers (10 oz or larger) from 12/5 – 12/12. Take a picture of your receipt and email it by 12/17, details here. You’ll then get a $10 Walmart Photo Center eGift Card. You can go here to read all the details. Update: You will probably get a confirmation in less than 24 hours,
telling you they will send an email in 48 hours, so be patient.
It doesn’t come right away. (Thanks, Iris!) It looks like the official offer on this is no longer available, but you can email your receipt to email@example.com. (Thanks, Kelly Kouponer!)