Tigs are far superior than migs but for "most" auto building a 130amp mig will do the job.

If a Tig is what your after they start around $1200 for a smaller unit from miller,hobart,HTP america.

Migs start around $300 for a 120-130 amp unit ,i paid about $600 with tank for my miller 130XP (110v) and have had it for a number of years without any problems.

Far as learning to weld classes are the "best" way to learn then you get not only the hands on teaching but also get the book knoweledge. If you have any friends that are welders then thats also a good way to learn,i weld for a living and have takin guys at the shop who have never touched a welder in their life and had them laying good looking Mig and "decent" lookin Tig welds in under a day. Its not that hard to lay a decent looking bead but does take practice to become good.

And Craig you are VERY correct with your thoughts that a welder gets PO'ed when someone critisizes their welds ....we are a very proud (and egotistical bunch)