go to a tractor place that has tractors in a color you like. and buy the paint and hardener.. you will want a gallon of paint and a quart of hardner to do your car. should last a while if you take care of it.. but there are some economy acrylic enamel auto paints that are not much more than the tractor/ impliment paints, but there all mail order so you have some shipping costs ontop of that..
don't get the rustoleum 'specialty' enamel from the hardware store. it's just Rustoleum in the correct colors to match the tractors