I would reccomend against Rustoleum. There basic 'protective coating' has no UV inhibitors, is Alky'd enamel and is not really meant for this use. If you step up to there professional line, it is basically the same. If yo step up to there urethane product, it is nearly the same cost as the Summit paint.. FWIW, Summit pain is Kirker, and decent paint, but also www.tcpglobal.com
has there 144 kits, which is 144 colors to choose from for $144 for the kit ( material to paint A vehicle ). the price may be diffrent now, but they have decent cheap paint.