I know people knock them, but I use a 220v harbor freight mig. It will do up to 5/16 with flux core and 1/4 with gas and it has a wheel kit and place to put the gas bottle on the back. Got the welder and the auto dark helmet for around $200. My only problems are that the cords (power, ground, and gun) are short and you have to add a plug to the power cord. But I've learned to deal with these characteristics and I have no complaints. The welder will put down a nice bead and I'm not a professional welder by any means. My dad has a used Hobart Handler 120 and I've as successful, if not more successful with this welder in comparison. I settled on this welder because I really couldn't afford a $700 welder then, and I still can't. Oh, on a side note, I've found petroleum jelly works purty good at keeping spatter off the gun tip.
--Justin