Speak to Potato as too the best way to paint a bike ... as for cost

How long is a piece of string and how deep are your pockets .... some paint systems are pretty freaking $$$$

From what Ive seen .... $200 per litre is a good starting point .... anywhere up to about $800 per litre ... but depending on the paint system you might need different types .. ie base coat, metallics, tints, pearls etc etc.

Its a very deep rabbit hole.