If it was only submerged for a couple of hours or so, and it just recently happened, there is a good possibility that most of the vehicle could be salvaged. I mean, if the stream wasn't contaminated to the point of being smelly or such, I would carefully remove the upholstery, seat and all, and "hang it out to dry". Clean the fuel tank, change all the fluids and see if it will start. Run it for a while and change the fluids again. You may be surprised at just how little damage was done. I say this because my daughter had a 93 Mustang that caught fire inside. Most of the upholstery had to be replaced, but the boys in clean-up at the dealership removed the carpet and scrubbed it a couple of times and let it lay in the sun for a couple days. Re-installed it and it smelled OK. Also, years ago, a Sears sales office was flooded during a sudden downpour. They sent trucks and loaded all appliances and hard goods and brought them back to the Mail Order plant where I worked. Now the lawn and garden equipment had water inside the engines and transmissions for well over a week by the time we got to service it. We drained the engine oil from every unit and cleaned water from carburetors and fuel tanks, started each unit and let it run for several minutes. Shut it off, drained oil and refilled, sometimes twice, but I don't remember hearing of any engine failures resulting. Of course we changed oil in transmissions, etc. also. I said all that to make the point that if one has the time, the vehicle may be "fixable". As to the value of the car, I can't say, obviously he has no insurance on the vehicle itself or you wouldn't be asking. If there are any good parts yards locally, they might give you an idea of the value. Sounds like the wrecker driver wants to make a fast buck.