To make some yourself, you will need terra cotta pots, some stones, super glue, and bathroom caulk. The best place to find terra cotta pots cheap is to look at garage sales and rummage sales, or ask any friends that think they have "black thumbs". I used to have bromeliads in these when I was an apartment dweller, but now that I have a yard, the smaller pots seem like more work than they are worth.
Glue a stone over the drainage hole on the bottom of the pot. Allow to dry, then caulk around the stone to ensure waterproofing. Super glue the superior pot on the top, allow to dry, then caulk around the edges to waterproof. Bury where you plan on having the veg grow, leave the top exposed for adding water.