Custom mixed two-part polyurethane auto paint at Sherwin-Williams and a gravity-fed detail gun at Harbor Freight. $40ish a pint of paint and $15 for the gun. Borrow or rent a compressor. Wear a canister style mask and woodshop googles. Practice first on objects like beer bottles or cans until you've used up 1/3 of your paint. Let your practice targets dry and look closely at the quality of the surface. Don't be in a hurry. When you learn how to lay down a thin and smooth layer without orange-peel texture shoot your frame. This kind of paint is really tough. If you let some of it harden in a plastic cup for a couple days it becomes the consistency of hard rubber like a toy super-ball.