Free: Contests & Raffles.
Designer foods are great for dogs with issues. All the rest of them will do fine on a quality name brand food. People think higher the protein the better the food. Can be quite the opposite effect. Dogs need a balance to maintain weight and muscle.
I wish I could find a dry food my Hound could eat. Everything I've given him so far causes ear infections. Even the hypoallergenic types. So I've been having to make his food. He eats better than me and my hubby, lol.