No, I'm not nuts...really!

I painted a ford ranger with spray bombs about 6 years ago, i used tremclad gloss brown. It was a beater anyway with rust scabs all over it and a few rust holes and dents. So i did some cheap, dirty, and fast bodywork and prep to it and spent a weekend on it. It turned out great, and for the $60.00 total i had in it for materials i felt it was worth it. It proved to be extremely durable and i could even pressure wash it without the paint flaking or coming off. It faded to dull brown after a year or so, but it did the trick and it looked a lot better than it did when i bought it.
It all depends what you want out of the car. If you want a finish that will last, buy conventional automotive paint and prep properly, if you just want it one color for now, don't be afraid to go cheap, just be aware, it will take a lot of work to remove the cheap paint when it comes time to do it properly.
Your call.