Materials can easily be $5000++ Most body shops charge $100 and hour. One man for "1" 40 hour week is $4000. We are up to almost $10 grand. If there is anything more than sand, seal, prime, base coat, clear coat, wet sand and buff it may very well cost $20,000+ That is no metal repair or panel replacement.
As usual, someone beat me to it. What I am going to say is a combination of what others have already said.
I am not a professional body and paint guy, but I am a very good body and paint guy. Like ToolmanMike said, Materials will EASILY be $5,000. Besides paint, there are primers (epoxy, high build), sealer, cleaners, hardeners, reducers, spray gun liners, mixing cups, clear coat, sandpaper, masking supplies, etc. If you go with a budget paint system (I like TCP Global's house brand), you can beat that $5,000, but if you go with a major brand, it will likely be over 5,000. As mentioned, most shops charge at least $100 +/- per hour for labor. That means that if a guy spends 6 hours masking, priming and unmasking your car, you just spent $600. Then he spends 6 hours block sanding the primer with guide coat and cleaning the car off. There is another $600 in labor. Then he applies glazing putty to the flaws he found, blocks them and sprays on a little more primer and sands that. 8 more hours and another $800. Then, once the body is perfect, the shop will either wet sand the high build primer as final prep or apply a final coat of another primer to wet sand. Either way, they will have to wet sand the primer with several grits of paper (320, 400, and possibly 600) to get rid of all block sanding scratches to prepare the body for that perfect paint job. Then he has to thoroughly clean the car. Wet sanding is a messy proposal. There is another 10 hours, $1,000. So JUST to spray and sand primer you are looking at about $3,000. Wow. That does NOT include ANY body work, rust repair, disassembly, assembly, pre primer prep, prepping and painting the backs of fenders, doors, hood and decklid. Plus the time it takes to prep, mask and paint door jams, engine compartment, etc. Plus, do you want the bottom of the car sprayed with something? Any amount of rust repair and major body work is EXPENSIVE, and repair panels are not cheap. So you can blow through $20K very quickly even with minimal body work.
Now it is YOUR responsibility to find the right place.
@barbee6043 is right when he says to go to a car show and ask owners. Then talk to the shop and try to get some references on their previous restoration paint jobs. Just because a shop does competent collision / insurance repairs doesn't mean they are the place to paint your classic ride.