Chargebee works on top of payment gateways like Stripe or Braintree. They give you more flexibility around subscriptions than those payment gateways support out

Chargebee works on top of payment gateways like Stripe or Braintree. They give you more flexibility around subscriptions than those payment gateways support out of the box. Plus they don't charge you a fee (excluding payment gateway standard fees) until you make your first $50k in revenue with them. Your other best bet is Recurly. They have lots of options for subscriptions but it may not make sense if you don't have any revenue yet.