Which Mig welder to buy?

Lots and lots of threads on this

Buy one locally supported. In this area two welding stores support both Lincoln and Miller

Buy one with gas option.

110 vs 220. Do hard thinking about capabilities. If you don't do anything except bodywork, and "light" frame work on these cars, a GOOD 110 will get you buy

RUN GOOD POWER to it. Install a "heavy" wired outlet to minimize voltage drop, and don't make the mistake of using a long, small extension cord.

Consider used. If you can try it out, Estate, garage sale, I've seen some fair buys.

Be leery, tho, of used gas bottles unless the seller and you can run them by the local bottle supplier and OK it