Driver fender is a hot mess...

I have a stud welder and slide hammer, hammer and dollies, and a lot of time this winter. I think it is a "get it straight enough to not need an embarrassing amount of filler and make it work" situation. $300 for a unknown used fender and $600 for new... I'm thinking dance with the one you brung. I am just worried about getting the body lines back, because right now they are obliterated.

PS: Heat is an awesome way to get body filler off!
That is what I would do.
I bought two sets of fenders, 4 in total before I got a really nice set for my Duster, both of the ones I ended up using I had to put aftermarket bottoms on, but they were straight.

The other two were rust free, but beat to crap from hail damage, there would have been more filler in them, than putting the fender bottoms on the rusty ones.

All these fenders fooled me when I bought them, they looked good, had paint on them and looked straight, until stripped to bare metal.