A payment gateway is a merchant service, provided by an e-commerce application service provider that authorizes credit card or direct payments processing for online businesses.
Chec sits on top of payment gateways and gives merchants a suite of eCommerce functionalities that payment gateways do not provide.
You can choose to accept payments with PayPal and Stripe.
Enable your payment gateway on Chec here.
Payment gateway fees - There will always be a cost when accepting payments.