It's sad but you just have to find one you trust. I'm thankful the last couple of vets I've had have been wonderful, but I went to one once that I swear charged me $300-400 every time I took my dog in. I finally got suspicious when my neighbor took her dog in because it had fallen off the couch. She (this vet) checked it and said its leg was broken and would have to be reset. She wanted to charge them $800. My neighbor took the dog to another vet----and the dog's leg was not broken afterall. It was just a sprain!!!
Shop around until you find one you feel is honest.