My 1st welder (Lincoln Weld-Pak 155) was purchased so I could refurb a 1987 F150. Even though it was wired for 220v, it had more than enough for welding autobody sheet metal with flux core.
For replacement metal, I just went to a scrap yard and purchased an old car door shell. The gauges of sheet metal salvaged from the door were enough to make the necessary repairs to the wheel arches and radiator core support. Also, the stamped contours from the inside of the door shell provided lots of options for making uniquely shaped replacement pieces.
Just my experience . . . don't plan on laying down full beads of weld. The thin sheet metal will burn away too quickly. To weld patches, use very quick welds, spaced around the patch. Keep doing that until you connect all the dots.
As mentioned above, Fitzee's Fabrication (
https://www.youtube.com/@fitzeesfabrications) is full of great info.
Another I like is HalfAss Kustoms (
https://www.youtube.com/@HalfassKustoms).
Both make body work look easy.