Mig welder suggestion

Just traded off my little mig welder that was a real good welder but too small for some of the jobs I do. What I need is something that will weld 5/16". I have looked all around and see several rated to weld 5/16 but right now I don't have $700 for a Miller/Lincoln. Would love to get a top notch unit but it just can't happen. Too many house projects taking up money too. Does anyone have a recommendation for a good mig that'll weld 5/16 in one pass that costs less than $450 shipped to my door in IL? By what I'm reading I need at least 140 amps to do the job correctly. I have 220 in the garage so going with a 220 unit is fine.

BTW: I already have a cart and bottle, just need the machine