In reply to iksander:
Yes, tried one once. They don't have adjustable resistance, and the resistance they come with have is minimal-to-nonexistent. So it's hard to make it any more strenuous than a walk. Also they're super-flimsy.
Worth keeping an eye on eBay, though -- they often have used Versaclimbers, and sometimes knockoffs of the Versaclimber (with adjustable resistance) will show up even more cheaply.