Man if its 50 per corner I might as well buy the tool
A) Again, don't quote me on the price.
B) Have you ever tackled a project for the first time, something you'll probably only ever do once or a few times in your life? It's usually cheaper than paying someone else with experience to do it, but it's rarely as good a quality and it's almost always more of a pain in the ass.
It's an upside/downside or "risk/reward, cost/benefit" analysis, keeping in mind the cost of a replacement fender of the correct matching paint if you totally ruin your existing one in your DIY learning process.
Just food for thought. And, again, please do not quote me on that pricing.