You can use any type of spray paint on a plastic item; however, some types are better suited for certain plastic surfaces than others. Without proper preparation, absolutely no kind of paint will last on plastic. Learn which paints fit with each type of plastic; know the proper way to promote adhesion and apply the paint, or flaking and sagging will result regardless of the type of finish you choose.
Though any type of paint will bond with properly prepared plastics, none will adhere to those that aren't. Plastic is terribly suited for paint, because it lacks the ability to absorb paint adhesives and is also very slick. Painting pros know that coarse surfaces hold new finishes much better that slick ones. To ensure long-term durability, knowledgeable painters condition plastic for better adhesion by abrading it. Before adding any sort of paint to plastic, scour the item with sandpaper until every part of it feels rough. Choose a relatively fine grained sandpaper between 100- and 120-grit; avoid lower-grit sandpapers which could roughen the plastic too much and carve ugly grooves and scratches.
Latex spray paint is well-suited for plastics that are not subject to duress. Unfortunately, it will not hold up on plastic exposed to friction, constant cleaning, and consistent handling. For these types of plastics, opt for an acrylic spray enamel. This particular paint is far more durable than ordinary latex and more flexible and less toxic than oil-based enamels. It is also quite easy to clean and can hold up to significant duress.
When amateurs try to apply spray paint to plastic, they tend to see runs and heavy sagging in the finish. Because plastic is slick, it tends to reveal subtle flaws. For a professional-looking painted finish, apply several light coats instead of one or two heavy ones. Hold the can at the proper distance -- 8 inches from the plastic -- or sagging will prove likely.
Even abraded plastic is not suited for paint. Before adding any type of paint, apply a bonding base primer. Use latex primer for plastic not exposed to duress; choose an acrylic primer for plastic items subject to friction and/or consistent handling.