According to this FAQ on their website in 2014 (Dues Increase Q&A | American Club Taipei), membership costs NT$ 156,000 to join - there should be monthly fees as well as usage fees
I just spoke to the Membership Office at the ACC. The current Joining Fees are NT$ 140,000 (refundable) + NT$ 315,000 (non-refundable) = NT$ 455,000 total