The free version has a small 2% transaction fee associated with Stripe payments. There are no transaction fees on any other gateways. The 2% fee allows us to continue supporting the development of a great free plugin for the community.
The paid version of Payment Page removes the 2% transaction fee. See our pricing plans here.
Stripe's and PayPal's own processing fees and terms are separate from any Payment Page fee. Check each provider's current pricing for your account country, payment method, and transaction type.