Hit the Thrift stores and look for old aquariums. If you don't care if they hold water, why spend the money on something that does? Grow small plants that won't outgrow your terrarium but will still be fun. I grow miniature orchids, club mosses and Sundews in terrariums.
If you can fit in some Baker's racks, add some LED lights (at least 6000k but low tempurature), you can build an incredible indoor garden. (The neighbors will assume you have started an indoor pot farm).
Have fun!
