Paper Cups, usually used for Hot Beverages work great as temporary containers or as small starter containers.
After you drink your Hot Starbucks Beverage, gently rinse out the cup with clear water and set upside down on a paper towel or rack to dry. When the cups are thoroughly dry, you can stack them for easier storage.
I use most of my paper cups for seed starting and for setting in young plants started hydroponically.
The Paper Cups usually last about 30 days under normal watering conditions, after which the cup can begin to discolor. At this time the plant can either be removed from the container (the cup is easily cut away with scissors) or the withering cup can be dropped into (stacked inside) a newer cup in which case you can get about another 30-days growth.
Also, I like to give baby plants as gifts to my friends and family. Starbucks Paper Cups make attractive and inexpensive temporary plant containers.
Finally, when a Paper Cup is completely worn out and I have cut open the cup with scissors to allow the young plant to be moved to a larger container or a permanent garden location, I will cut the remains of the cup into flat pieces in various sizes. I place pieces of the dissected paper cup into the bottom of my garden containers with large drainage holes to prevent the soil from escaping while still allowing good drainage. By the time my Starbucks Paper Cups are ready for disposal, there is little (if anything) left to toss in the trash.