Our food budget for the trip is $180. Since I was sure we would overindulge ourselves whenever a buffet was involved, we mostly are planning to eat two meals a day. This morning our breakfast is free. We are staying at the Suncoast (off the strip), and one of the freebies they sent me in the mail is for two free breakfast buffets.
A lot of people would find it hard to eat dinner for two for $20. But this is Vegas. Between the possibility of "earning" free meals through gambling and some of the more aggressive dining options - Ellis Island, as an example, features a sirloin steak, soup or salad, baked potato, vegetable and beer for $7.95 - I am not too stressed about making budget.