Back to Gasless Mig (more accurately called Flux Cored arc welding).
They have their uses. eg. welding outside, where wind will waste an awful lot of Mig or Tig gas.
Flux Cored is also more tolerant of older, dirty or rustyish metal, (like a stick welder).
Biggest problem, is that the really cheapest ones, are AC welders, (like a stick welder).
They Splutter & Spatter and make welds that look like you have never used a welder, (Arc, Mig, Tig or Oxy.) in your life.
With patience & practice & fiddling with speed & power (volts/amps), you can sort of 'stick metal together' with one.
They can be vastly improved by converting them to DC, using suitably rated diode rectifiers.
You can also add capacitors, to even out any DC pulse, if you are worried about that.
If you don't have knowlege, experience, confidence & time to do this,
Spend the extra money and buy a Gas/Gasless Mig which should have a DC output, and use it gasless.
You need to ensure the polarity is changed to Negative Electrode for flux cored.
For thin panel steel you still need to do stitch & cool welding to prevent burn through & distortion.
Heaps of u-tube videos about all this stuff, though most are not worth your time.
Cheers, Daryl
