Plugin allows to add negative fee (discount) using shipping or payment methods.
Not registered version is fully operational. It has only one limitation. Only 50 discount will be added. Try before buying.
Compatible with NopCommerce 3.40, 3.50, 3.60, 3.70 and never.
How to install and configure the plug-in.
http://www.foxnetsoft.com/documentation-NopNegativeFee
Link to our site http://www.foxnetsoft.com/nopnegativefee