In my area you can get nice, thick, food-grade buckets (from pickels and mushrooms, mostly) from some delis for free. I do worry about leaching from plastics, but I guess not enough to stop me from using it. Terra cotta isn't terribly expensive and will last for a while - I like to buy mine during sales at craft/fabric stores, though it can be hard to find large sizes. (If you use terra cotta and it freezes in your area - which seems unlikely? - you should empty out the soil before cold weather starts.) If you want to use wood, look for untreated, rot-resistant wood like cedar - unfortunately that usually means spending some $$.
You can buy varieties of many plants that were specifically developed for container growing. Usually they produce smaller fruit than what you're used to buying in the store, but they'll produce a lot of it in a small space. Some plants, like salad greens and many herbs, will never notice they're in containers.
With container gardening you have to do a really good job keeping up with the watering. If you are going away for a long weekend and not expecting rain you'll need to find someone to water your plants. (At least, this is the case in my area.)
There are a lot of good books on container gardening; I like The Bountiful Container.
Good luck to you!