If I'm only in town for a month, do I just pay the $10 month fee or do I have to pay the annual fee as well?

I believe the annual also, but not 100% sure. You find someone with a blackcard and you can go as their guest.

Hi, Cassandra! We do not have any short-term one-month membership options at this time. The annual fee is due 30-60 days after the start of your membership at the beginning of the month, and is charged unless you cancel by the 25th of the month prior. Hope that helps!