Where in Bangkok can a young woman get HPV vaccine?

Cost?

Any hospital.  Costs about 2,500 baht per injection and 3 required so series is about 7,500 for the vaccine plus cost of 1 doctor consultation. Occasionally hospitals have promotions at lower price.  Bangkok Hospital currently has a promotion https://www.bangkokhospital.com/index.php/en/packages-promotions/vaccine-hpv-child

 

Note that only original Gardisil is available here not Gardisil9.

 

If the girl is Thai, it is being given free at some schools but not yet consistently nationwide.

 

 

as an additional information for OP and according to my doctor, HPV vaccines also are effective in men.