For those looking for one-on-one sessions, Red Door Yoga is a good option. Private classes are 600rmb a session, but alternatively, you can also sign up for one of the morning classes and cross your fingers that no one else turns up. Drop-in classes for those group sessions will cost you 150rmb each time. 6 month to 12 month memberships also available. Note that since this one follows the traditional Ashtanga practice, the place is closed on full moon and new moon days.