does anyone know of some good affordable yoga classes in Kunming?

The best Yoga in Kunming is by Yutao studio, my favourite is they give you meditation period before and after class to adjust yourself, from my memory, can try the first class for free

check:www.yutaoyoga.com/

Since the OP mentions affordability it's worth mentioning Shanti Yoga. The quality of instruction could well be better than at yutao: last time i was there at least, the main teachers had all done Yoga Alliance 200 hour courses - but probably haven't registered since it costs a hell of a lot by Chinese standards - and the studio now has an affiliation with the senior Chinese Ashtanga guy (forgot his name unfortunately).

Address: 19th fl HuaErDun DaSha, corner of BaoShan Jie & QingNian Lu.

Tel: 08713133088

Map here: www.xtyoga.cn/CyberFiles/html/index_11_1.htm
(Note QingNian Lu - the road that runs horizontally across the middle of the map, ACTUALLY RUNS NORTH SOUTH! :s)