I hate to be negative about something like this, but I feel like I need to speak up, so I'll try to be as eloquent as possible.
While it is possible to save thousands of dollars on a paintjob by using this method with cheap materials and get a result that looks great, there IS a down side. That downside is lifespan of the paintjob. While if kept in a garage, it will last a good while longer, it still will not last as long as automotive paint.
It sounds great when you don't have the cash for a prfoessional job to justify it with the "My own labor is free" outlook, but take it from someone who has done it the right way and the wrong way- It's a lot easier to say,"I'm going to strip all of the bad paint off this car" than it is to actually do it.
It takes a really, really long time to strip a car with rustoleum on it, and you HAVE to when you decide to do it right, because unlike automotive paint, you can't paint over it; it will simply let go and you've wasted money again...
Advice is free and you can take it or leave it, but here's mine:
IF you are going to do a roll on paint job, please, PLEASE at least invest in automotive grade materials, so it will at least adhere to the car properly. You'll thank me later.
Oh, and if you don't believe that look here:
http://www.stangnet.com/mustang-forums/threads/ever-see-a-car-youve-sold-and-wanna-cry.854112/