Not a site, but if you show up well enough dressed at a number of hotel chains in the morning, many offer free, full breakfast.
I'm a member of ebates and rakuten and honestly, I have not found a single thing that I would want to buy. I don't shop for fun...I'm very pointed in my search. If there's a 5 quart bottle of 0W 20 motor oil out there shipped for less than $18 using one of these, I'm all ears. (that's what I just paid on Amazon....and no, neither of those portals worked for this).