Want to save a small fortune when staying at the Mirage, Venetian, or Treasure Island ? Simple! If you stay at the Mirage, save your money and walk across the Strip to Denny's. They serve very good food at very good prices unlike in most Strip restaurants where you will pay a small fortune.
don't eat at hotels There are tons of cheap eats on the Strip..I too never eat at any hotel I stay but prefer to walk across to an eatery like Striburger, which is right across from Wynn and is cheap and tasty. I would also suggest Enoteca Otto Pizzeria at the Venetian.
go off strip or downtown for eating out in Vegas Hotel food isn't always that expensive..It is usually good value if you eat at the hotel cafes. Though of course, if you really want cheap prices you need to go off strip or downtown. Gold coast or Orleans are my suggestions. They're off strip but you can get on their free shuttles to get there from outside the side of Bill's casino.