If you want made in USA, best look for a used Miller dialarc or similar - the new Millers are apparently "assembled" in USA (from foreign parts), for the most part - and especially in your price range.
I've seen a couple of Dialarc's in CL recently, one went for $350, other was listed at $400. Woulda bought one of those, but I already have a 250 amp ac/dc by Solar (old enough it's still all copper), a 4 yr old Miller 252 (when they were supposedly still made in USA) with 30A spool gun, and an Everlast I-tig200T (200 amp DC tig, 160 amp stick with dig and hot start).
At least Everlast is honest enough NOT to put a big USA sticker on it with small print saying "assembled" - plus it's got a 5 year warrantee. Oh, and it weighs 22 pounds compared to about 90 for the Miller, and will run stick on my 8 kw genny 'way out in the field when I need it to.
We'll see how it goes; Tig is not an essential to me, so I was willing to chance it for 1/4 the cost of the same features in a Miller :confused2:
Not sure I'd survive tellin' the wife (as cool as she is) I was buying another welder at this time anyway
Absolutely nothing you could buy new at that price is gonna be made here any more - period.

Sorry, but that's just the way it's gotten... Steve