Quality wheels can (unfortunately) be somewhat expensive. I know a lot of folks use Wodent Wheels for their gliders -- they're one of the more widespread brands that you'd be able to find.
We are as gods to the beasts of the fields. We order the time o' their birth and the time o' their death. Between times, we ha' a duty. - Terry Pratchett.
"Men have forgotten this truth", said the fox, "But you must not forget it. You become responsible, forever, for what you have tamed. - Antoine de Saint-Exupéry