I follow but some issues you need to be aware of.
Got to find one in complete at least "could be saved" condition for <3K. Tough these days.
Make sure you are looking at sold/completed auction prices. Asking is just that.
If you do not have experience with correctly restoring a soda machine and do not have a network of painters/platers coin mech restoration experts lined up, sorry to be blunt but you will not be able to restore a machine at a profit. A DIY
restoration on a machine that was a clean original to start with should be a death sentence crime.
Walk before you run. C-72, USS-64, V-63, and many others are fine starter machines.
Creighton
I wasn't looking at working on/restoring one in this hypothetical, but rather getting one already refurbed at a hopefully lower price than a typical refurbed might realistically sell for, and I was wondering what that value was, what a nice refurbed might sell for.
Using the examples others mentioned so far in this thread, it looks like $6500-$7000 might possibly be the window. If that is pretty fair, then if I could score one for $4000-$5000 that would probably be a pretty good deal, I would think.