Question about dog food

My dog is allergic to corn, wheat, soy, what is a good dog food, that is not expensive for him, he is a American bulldog, does Purina have a brand??? I looked up a few, but they’re very expensive, help????

 

Answer from Dr. Gaylord Brown:
Expense is relative. If the food prevents the necessity of medications, you may actually save money! The key to a hypo-allergenic diet is to have a unique protein source such as salmon, rabbit or venison, and a unique carbohydrate source such as brown rice or potatoes. We are using a Blue Diamond salmon based diet at our sanctuary which may meet you needs, but you must read all labels to make sure there are none of the offending products. Most diet changes require about four weeks to show results.