I recently saw an ad for a once-in-a-lifetime amazing gardening product, guaranteed to change my life. It was Styrofoam balls to put in the bottom of containers, offering a lightweight alternative for drainage. And if I ordered right now, I got another set free and it was only $29.95. Hey, it's a great idea, but for that kind of money they better come over and plant the pot with rare flowers.
Any craft store will sell you the same for around $4.
The Styrofoam lasts forever and makes moving the pots much easier. The most important thing for container growing is proper drainage; many gardeners put an inch of gravel in the bottom of the pot, which is fine if the location is pretty permanent, especially for big containers. Even if the pot doesn't have drainage holes, adding something like the Styrofoam balls at the bottom will keep the roots of plants from becoming waterlogged.
Since Styrofoam will be the last thing left on the planet after cockroaches and Keith Richards, use what you buy. Fill up the bottom of your pots with it and make some cool crafts with what's left over. Pretty snowmen are the first thing that comes to mind.