WooThemes - WooCommerce Payment Gateway based Fees v2.2.1
The extension enables you to add a fee to an order depending on the chosen payment gateway. The fee can depend on the price of certain products in the cart or the cart total. The automatically calculated fee can be changed later by the shop administrator the order page at any time. You can also apply a fee manually to an order if the customer i.e. wants to switch to another payment method after the checkout process is completed.