They are all for sale. Nominally cheaper than outside. I made a detailed comparison, which is actually more expensive than Funan 100.

Duty-free shops refer to shops that have been approved by the General Administration of Customs, set up sales places and supervised warehouses for storing duty-free goods in places approved by People's Republic of China (PRC) and the State Council or their authorized departments, and sell and supply duty-free goods to specific targets.