If I planned to do the same, how much $ should I budget?
That depends on a few things - how much you do yourself and how much you spend on supplies.
I repainted a friend's Hyundai recently. It took us about 6 hours to mask off areas not being painted (tires, engine bay, etc), and he had spent maybe a hundred getting it ready for the paint, with rust repair and other stuff. It took me another 12 hours to prime, paint and clear coat the thing. Figure $100-$150 per hour for a body guy and go from there. If you have extensive rust, dents, dings or collision repair to finish first, there's no telling how long such an effort would take.
Assuming you're just painting the thing, with no repairs necessary, paint can run anywhere from $100 per gallon, to much much more. Hyundai guy bought some really nice stuff for $500 a gallon (no kidding), and stuff suitable for a Porsche will run even more. I like DuPont paint, which won't kill my wallet and stands up to time. He also bought some high-end primer and a clear coat compatible with it all. In all, about $850 in supplies.
I painted another friend's BMW and she paid about $420 for paint and clear, as well as associated supplies.
If you buy bondo, figure about $60 for a big can of the stuff, and perhaps $50 in sand paper. Roughly the same with fiberglass. If you replace an entire fender, prices vary - same with floor boards, rocker panels and such.
Hyundai guy's job was quoted as $11k from a local painting professional. A local detail shop quoted me $400 to detail my 108 before I sold it, which included engine bay, "paint restoration" (a nice wax job, in my mind), interior detailing, etc. I didn't go for it, as I have a vacuum and access to armor-all.
Your biggest cost savings will be in labor - if you can do a lot of this work yourself, you'll save enormous amounts of $$.