Nice looking containers, but expensive. I bought a white plastic version of a half-wine barrel with black "iron" bands which were also made out of plastic. I had to drill out some drainage holes in the bottom, and the whole setup cost me $45.00 ... on sale. Great for a patio tree, but mount the container on a dolly.
Scott....a cheaper alternative: Use the deep, rectangular, plastic storage tubs that are sold in any Home Depot/Lowe's-type stores. For less than $10.00 you can get a tub holding around 18 gallons of growing medium/soil. Just drill/melt holes in the bottom-sides of the tubs and you are good to go. There are also large, round, plastic "pots" that I see all over, that have rope handles which look more like a conventional pot, but they usually come in bright, gaudy, colors.
The tubs, because they have straight top edges, can be placed very close to one another without losing too much room. They make nice neat rows if you have a good number of trees. They are relatively easy to lift from the handles molded into the sides, too.
Hope this idea might help.
Frank