Use ANYthing for a pot - from simple, plastic, to wood or cement pots, troughs, urns, wire mesh, or barrels. Choose one that is in keeping with the surrounding area and the feeling you want to create.
You don't have to buy a container at all. Use items with whimsical value like old kettles or leaky boots. It's surprising what can look good when planted up with flowers. There is so much variety, we can barely contain ourselves - pick a topic and go to pot!