HVLP?

If you're just priming or painting frames and hard parts a low budget gun will be fine.
When you start shooting metallic you may find different.
I agree if you're going to start painting cars for a living or even paint a car I would probably shoot for something a little better but just doing brackets and core supports and stuff like that that's really not going to get buffed and polished for the most part one of these guns is going to work perfect.
Again I watched a lot of you boob videos and the one I like best was the guy that used the home Depot oil based industrial Rust-Oleum and 20% acetone...
After I used it I swore I was never going to use a rattle can ever again. I mean $10 for a pint of that paint mixed with 20% acetone I'd go through five cases of rattle cans.. the coverage is way way better as well... Now I still do some things with rattle can that I can only get the color in..
But if I would have had to have rattle can that entire bottom of that truck cab it would have been a couple six packs of cans...