Paint for a plastic Barbie Volvo wagon

Hey i was wondering what do you have to do to paint a plastic Barbie volvo wagon? I don't have any spray guns or anything, we want to use like the little paints (neon green) you get from walmart for models. would i have to prime it and stuff or just paint it? I am doing this for a friend, like to get started soon! any help with it would be greatly appreciated!