Decent 2nd hand stuff still aint cheap. Best of the cheaper used stuff is probably a Snap On turbo mig, rebranded Cebora mig, good welders, and a decent resale value when u want to shift it.

Just get a new Clarke 130, decent wee welder for the cash, and capable of most stuff. You can always pick up a mega cheap used stick/arc welder for heavy chassis or trailer stuff.