Most fast food restaurant websites offer coupons from time to time. Many times, they will put them in the paper or even have them on the counters. Higher end restaurants may have daily specials also. Talk to the manager and see what your favorite restaurant offers.
There are web sites where you can get "gift cards" for restaurants at discounts. These gift cards work very much like the store cards. Many times you can get them at a discount on sites that resale unused gift cards. The savings will add up and it will give you an opportunity to enjoy a special restaurant at a savings. You can purchase these gift cards online. Just Google your favorite restaurant or resale gift cards.
You could also give these gift cards as gifts for a special couple to go on a special date. They will thank you, and you will feel good both for giving the gift and for the savings that you made along the way. Always do the research; it might just surprise you on what great deals you can find.