How much would you be willing to pay per game hour?
Good question. According to this blog, "30 yuan will buy you 4000 minutes of gametime and 15 yuan will buy you 2000 minutes of gametime. That's $0.06 per hour played."
That works out at US$4 for 4000 minutes, which would be about £3. Obviously, Chinese pricing reflects the local economy. 4000 minutes is 66h 40m, so say that's 2 hours a night for a month. Lowest UK monthly subscription is £7.69, so if I could get 4000 minutes for £7-£8 that expired after 90 days, I'd probably go for it.