I started doing this with all kinds of plants after starting college. I don't have my stacks of pots, so I make them out of applesauce cups, plastic water cups, cereal containers, anything waterproof that is the right size. I've used some for water culture, and some I drill holes into to use as containers. They are really great when you want to propagate something for a friend, convenient and cheap. Then the friend can spend money on a real container, if they want. Personally, I kind of like a primrose in a frosted flakes container.