It's frustrating, isn't it! I'm lucky in that we have a vet nearby who is actually in it for the animals - She doesn't charge for travel, only charges for what she uses, always comes if she can... I often just call her and explain the situation, drive over, pick up some shots/bandages and such, and then pay her in a few weeks. She never asks for the money, I nearly forgot one time!
However, because of this she doesn't have a fancy surgery - It's her garage, and year after year the other vets try to shut her down. Lobbying by her clients has kept her open so far.
The only thing is she doesn't have any of the more advanced equipment - Can't do large animal surgery or anything. So you have to go the other vets - They charge for time, travel, blah, blah, blah... A friends horse tied up on the weekend, she gave them shots and advice, ended up about $50 - The other vet would have come out, checked up, la-di-da and cost over $200.
I don't really have any advice... Just sharing the angst at vets who overcharge!