How much would a full coloured half sleeve tattoo cost it is very detailed and goes from the top of the shoulder to the elbow?

It all depends on what you want as far as color or black and gray. Most tattoo places charge by the hour and prices differ from artist to artist. Good tattoos are not cheap and cheap tattoos are not good. Best thing to do is find which artists work you like for the type of tattoo you want and then discuss pricing.