bladder stones

Our german shepard is 7 years old and developed bladder stones. Our vet prescribed prescription canned and dry food which is very costly. Will he have to be on this food for the rest of his life? What exactly in the food is causing the stones and is there another non-prescription food on the market that we can use at a later date if the stone is dissolved to prevent him from getting this problem again?

I would recommend talking to your vet about this, it depends on the extent of the stones.
   
If your vet is not willing to talk about other foods or anything then you could try ringing round other vets for recommendations.