You can also make your own. Just use a copper pipe and machine a base. It won't be as good as Kingpin material, but who cares when you're pouring -192c in there.
Mounting should also not be a problem. Cut a plastic board to fit the tube and drill holes for long screws. Insulation same.
Having the right chip, memory, board and a few backups and replacements, that is what costs real money. Unless you want to start with older hardware, which is always a good idea. You can easily grab some Hwbot records if you know what to bench. Do some research on that.