The powdercoating gun comes with a cup that holds the colored powder. The cup should be filled with no more than 1 to 2 inches of powder. The powder goes a long way, with 1/2 pound covering 10-20 square feet depending upon application. We selected the gloss black for this job. The cost for powder varies between $9 to just over $20 for an 8-ounce container (shown), and larger bulk quantities can be purchased at a discount.