Honestly I'd spend the money to have a pro do it. By the time you've built yourself a paint booth - which you really need to keep dust particles out of the finish - bought the appropriate respirator, paint gun and other supplies, I find it hard to believe that you'd save money doing it yourself. Maybe if you have a friend who does bodywork and can help you out...

I totally understand the appeal of doing things oneself, but painting metal that you want to look nice is one thing that I'd leave to someone who knows what they're doing.