I have a one man shop doing restoration in East Tn. I have done about 12 cars, total, in 10 years. I do driver quality work, not show cars. First you need to fully understand what you want out of the car when it’s complete. That needs to be communicated with the shop up front and they should share what that means for costs and time to complete. Parts can be cheap or expensive depending on quality. Body work can be repaired many ways, bondo over tinfoil to new sheet metal everywhere. Paint can be cheap to expensive. The list goes on. When I do a driver quality total job, interior, mechanical and body& paint it costs from 25 - 35,000. I charge $35 / hr and parts. That is pretty cheap and most shops are at least $45 - ?? There is no good cheap restoration. Pick a shop that asks you the right questions and gives you good answers to yours. I would say that a 1968 Fastback is a good start for a valuable restoration though. I have one of my own
Dan