My dog is broken

My dog Moose became sick a week ago. He would wake up in the morning and vomit. He did this 4 days in a row. On the fourth day I took him to the vet. I told the vet that Moose was going a little stir crazy because of the weather, he is not outside much because his paws get cold so fast and he cant walk, I end up having to pick him up and carry him inside. Because of this he had destroyed most of his toys and I believe he had ingested some of the pieces because I've seen him drop some toy stuffing out his backside when he does his business. So we thought it was the toy parts causing problems for him. The vet also ran a bunch of tests and took some x-rays. Vets also cost as much as people doctors. Ouch. We saw some stuff in his intestines and all his tests came out good so the vet put him on a bland diet. The food is some special blend by Purina or something like that. He was on the diest for a full week, then on Monday I fed him his normal food. Not a good idea, he woke up again Tuesday morning and vomited again. I called the vet once again and told them it was starting over again. The vet called me back and suggested I continue the bland diet for Moose. I went back to the vet and bought the special dog food for him this time I bought him only three cans of soft and a bag of dry. I don't like him eatting wet(can) food because it creates tarter on his teeth and dry food is so much easier to store and transport. The food he was previously eatting he had been eating it for more than six months. I hope it is just the food causing the problem and not someting serious.