[dremd]

I'd recommend that you avoid Flux Core Welding wire.
I weld with a smallish 220 Miler Mig machine (mostly steel) but I also use it with aluminum occasionally.

Best advice I have is to get a mig welder, a pile of scrap (similar thickness to what you want to weld), and just Practice Practice Practice.

I've welded with a Harbor Freight mig and it wasn't bad, the torch was terrible, but the machine was decent.

Oh and don't forget the plasma cutter.