Hanging plants are a great solution for constricted spaces like apartment balconies, but hanging pots can be pricey. For a cheap alternative that works in really small areas, try using a cheap bathroom organiser.
At IKEA Hacker, Sara P details how to use the Visen bath caddy as a hanging garden solution — just add some felt to hold the dirt in and hang them up. It's a clever way of gardening where space is tight, and you could use a similar tactic with any hanging organiser from your nearest $2 shop. (IKEA Australia no longer seems to sell the Visen, though it used to — I have one in my own bathroom.)
bath organizer to succulent garden [IKEA Hacker]