Find a body shop/car dealership in your area and ask them about their excess paint, most likely this will be of the basecoat/clearcoat variety. Which you can thin the basecoat colors with lacquer thinner, urethane clear and lacquer clear will topcoat these base coat colors nicely! It is imperative that you use a respirator while shooting basecoat and do so in a well ventilated area, if not a booth of some such. Free Paint!