You can use lots of things that you have on hand, it doesn't take up much room and it doesn't cost a lot. Size doesn't matter as long as it's clear and is wide enough at the top so that you can plant easily. It should also be something you can cover with clear plastic, if it doesn't have a clear cover already. Select your plants. They should of course be small enough to fit easily in your container, even with several inches of gravel and soil, and they should also like moisture.
Most houseplants are okay.
You may also want to consider blooming plants such as miniature African violets, or variegated foliage plants such as a Polka Dot plant. Ferns of different textures in a terrarium make a great centerpiece. Add a layer of crushed charcoal to the bottom of your terrarium container. It will take care of the odor that enclosed plants eventually develop, and it will also keep the soil level. Even if you crush it, it won't do the job.