I believe money shouldn’t be involved.
Just match sellers and buyers together and let them figure the terms and transaction out themselves.
All that is needed is a way to find what you want and a solid system of building trusted profiles with ratings and such.
Not a simple task, but keep the money out and it will all be easier.
NixOS is exactly what you want.
You declare your configs in a way that you can just copy them to another computer and it willbe configured the same way.
I’ve never tried it my self, but I might for my next machine.