I bought a Hobart handler 180, and I love it. It is 220 volt, and can handle upto 1/2 inch. I think that might be pushing the upper limits, but it can throttle down to work with light gauge sheetmetal. However if you have to use a dropcord to get it out to your truck(as I have to) it can have an impact on the welders performance. Plus copper wire that heavy can get expensive quick.
So if you can get any work close to the welder I would suggest 220 volt, other wise get a 120 volt machine that is easy to move around and easy to supply power to. In other threads it is suggested you buy a welder that would run $1500 to $5000. Would I like to have one of those? you bet!! They have features and controls you can't get on less expensive models. So decide the most use you would have for a welder, add 15% (you never know)and buy according to your needs and budget.