actually, an idea is to make your own. Watch Craigslist/Freecycle for old broken skateboards, use 4 2x4s to make a small square, put the 1 set of wheels on each corner, wala. Plant caddies are awesome, but expensive and I don't like the plastic ones. They don't hold up to extreme heat w/o getting brittle and my cold causes them to shatter.
