We offer a few different subscription plans, but our month-to-month plan costs $24/month for US customers, and $34/month for international customers (shipping included).
Other pricing plans (for US customers only) are:
3 months: $72 (billed every three months)
6 months: $132 (billed every six months)
12 months: $240 (billed every twelve months)
You can find more information and sign up here.