We develop and maintain the integration with CiviCRM.
Opening an account with Stripe is free, requiring only an email address and password to get started. There are no monthly fees, just a per-transaction fee of 2.9% which is deducted automatically and recorded against the payment in CiviCRM.
Currently one-off and recurring payments by Credit/Debit card are supported. In the future it is planned to support additional payment methods.