Curves costs me $29 per month (US). I joined when there was a initial membership fee special of $59, which included 2 months of membership. So, essentially I paid only $1 for the initial fee.

The $29 is for a one year contract with the money deducted monthly from my credit card (deduction from a checking account is also possible). If you join on a month-to-month basis, the fee is $39 per month. With the monthly contract of $29, if you quit early, you must pay $10 extra for every month of membership (that is, if you quit early you end up paying $39 per month).