Once you have signed up with Restaurant.com, they will send you special coupon codes very often. This morning I received one for 80% off (which means a $25 certificate costs $2) with code PUMPKIN. This is good until Oct 25.
South Florida Dining also sends emails once you have signed up. You can see their specials at any time by looking at the Blue Plate Specials at the top of their page. I love the $30 certificates when they are on sale for $9.99 and I find they run these specials often.