I have not read the article.
But I can tell you this--good paint costs money. That's an indisputable fact.
$50 would not buy enough Rust Oleum or Krylon at Home Depot to paint a Wheel Barrow, much less a car--so if that's what is written in the article consider the author has not a clue.
Yes, there are YouTube videos of people painting cars on the cheap, and we all laugh--but nobody I know would really want to own one like that. Would you?
Go to any auto paint store, or talk to any good body man, and they'll tell you what good paint costs. I distinctly remember the paint materials (paint, reducer, etc.) to paint my 113 were well over $1,000 back in 2001. I suspect they might cost a bit more today.
One of the things that separates a great paint job from others, is the amount of time spent in prep prior to painting, and post-painting work such as rubbing. Time=money. In addition, a good paint job will have everything removed--and I mean everything--down to the body shell. Count on a few extra hours for disassembly and reassembly...