While a plastic cup and paper plates work just fine, if you want to level up your child's art experience, then get them a plastic art basic and palette. The upside to a basin versus a plastic cup, is that it is much less likely to tip over and there are holes that can hold their paint brushes rather them lying them on the table! Also, the benefit to a plastic palette versus paper plates, is that they are reusable... however, that does mean you need to clean them after every use! So, if they are using acrylic paints, you need to teach them to wipe off the excess paint with a paper towel first and THEN rinse them in the sink with water. Kids tend to pour a LOT of paint, so you don't want all that excess paint going down your household sink!