I would not go for cheap in China. Cheap = copy. Even expensive is probably copy. But cheap..definitely copy.

Depending where you're from (country), you might have trouble finding your correct prescription .... most Chinese eyes pop out of the head which gives them a "negative "- measurement and most western eyes sink in the head giving a "positive" + measurement... so positive is hard to find... glasses you can find anywhere... You can order contacts online from Hong Kong and pay the delivery (small amounts or you'll be changed import duties) ... just yahoogle some HK optometrists ... good luck..