UPSIDE: Get yourself a metal lathe at bargain basement prices. With a lathe, you can fabricate every other tool in the shop and machine handy things . . . that you cannot buy.
I’d have to say:
A lathe
A Bridgeport-style milling machine
A metal-cutting bandsaw
A welding outfit.
Sheet, tube, and bar stock, mainly in steel.
I was at a company that had those assets, plus a good all-round machinist. I was impressed by the variety of stuff he could make up to the owner’s specifications.