Restaurant.com 80% off
If you've used Restaurant.com before, you know the deal. If you're new, a word of caution. Each restaurant sets their own redemption rules so read the fine print carefully. Certs often exclude alcohol and require a minimum purchase above and beyond the value of the certificate.
If you are wary, I did the math and found these certs can save you 28%---47% off your total tab, which is pretty dang good.
Buying certificates at Restaurant.com benefits WalletPop.