You can buy wheels on tao-bao.com (if you have agents, who trades with tao-bao, in your country). Also you can buy wheels from KTM XC 250 07-12 model year, just pay attention to axle size, older KTMs has smaller axles.
I have bought set of wheels 21\18 from tao-bao, their price was about 200 $ + 20% commission of the agent + 15 $\1kg shipping. Wheels for KTM are more expensive.