used Wheeleez 30cm for yak cart

Hi, I'm looking for a pair of used Wheeleez or a place to get them cheaper then 74.00 listed online, I think I paid 50.00 a wheel in Fla at a beach rental place that had beach wheelchairs that saw a lot of use and the front wheels were 30 cm. I've had a ton of trouble with my current wheels over long halls on rounded rocks on Van. Island. Any ideas? thx
jt

Wheels from a power wheel