Check out your local tractor/farm supply store. They will probably have the paint in qt. or spray can.
Spray cans at dealer is about $13 a can, but it IS good paint. Much better protection, shine then others.
On this forum there is a section on how to paint one of these tractors, and it tells how much paint is required. I think you look under "ARTICLES" at the very top by FORUMS, CLASSIFIEDS, VIDEOS.