If you don't like spending a lot of money at big big stores like PetSmart or Petco, go to Canine Commissary. The owner owns 2 stores only, they have very good prices and they also have a frequent buyer program where you get like 10 bags of pet food in a year and you get the 11th for free.
They don't sell pets like most pet stores, they sell the rest of the stuff - dry food, wet food, cleaning supplies, beds, books, leashes, toys, etc. Friendly people too, if you can't carry a big bag of food to your car, they will do it for you.
We've been shopping there for years and they usually have better prices compared to the big chain stores.