Cash Back For Bookings and Other online shopping
You can get up to 15% Cash Back from Topcashback.com by booking (clicking through) from the TopCashBack website (I get a $5 referral if you sign-up for TopCashBack using my link below).
Once you have signed up, go to Travel section to see various cash back deals available from them. For example, currently Groupon is offering up to 15.50% as cash back for New Groupon Customers.
Other Good Cash back sites
Discovercard - Cashback from Discover Card. Must have the credit card with Discover.
Upromise.com - Upromise can direct their cash back earnings into a high-yield savings account or tax-deferred 529 plan, use it to pay down eligible student loans.
Following two are very good consolidator sites that allows you to check all cash back earning possibilities from all retailers and credit card issuers.
EVreward.com is a great one stop portal to check out all cash back and miles/points earning possibilities from all retailers and credit card issuers. Simply type in the name of a retailer and it will immediately let you know how much cashback or miles/points you can earn per dollar.
Cashbackholics - One place to see & compare the cash back rebates that online shopping portals are offering. Currently, it does not list details about miles/points earning possibilities.