Rewards programs -
Swagbucks - earn points for e-mails, shopping, games, quizzes, etc. Then turn your points in for gift cardsMyPoints - earn points for e-mails, shopping, games, quizzes, etc. Then turn your points in for gift cards
IBotta - cash back for groceries
Listia - earn credits when you sell stuff and then use your credits to place bids on items or transfer them for money!
Perk - Play free games and earn points then turn your points in for gift cards. Use my code 716c3952 and get 50 bonus points
RecycleBank - Does your community recycle? Did you know that you can earn points and turn them in for gift certificates?
Upside - Get cash back when you purchase gas and at some grocery stores with this app!
Coupon Sites -
Kellogg Family Rewards - turn points in for coupons
Hot Coupon World - this onsite community has great insight to deals at a LOT of stores and online. Has a great online coupon database to look for those coupons you need.
Saving Star - coupons that you link to your loyalty cards and then you get cash back!