You can also buy one from brutestrength.com. Their sleds are way less expensive the those at Elite. I bought one for my sons. Outside of the fact that it took a hell of a long time for it to ship-like more than 2 months!!!-they have been satisfied with it. I mean how can you go wrong with this kind of basic equipment.
By the way we also used the old tire with a wooden platform inside before buying the sled. That worked well too, but was a little harder to transport to the park.
Bottomline is sled pulling is a hellafied workout, especially for young developing athletes.