Ok let me give you an overview of NopCommerce
NopCommerce is one of the Best e-commerce project
nopCommerce is an open-source e-commerce project
you can use if for your online store/company or anything you want
you don't have to pay anything in order to use it,
You can modify it according to your requirements, add anything, delete anything, do whatever you want
You can downalod it for FREE, without any cost
when you will run this project , you will see on the footer of each page, it's written "Powered By nopCommerce"
You can do anything in your project except removing this message that appears on each page, as it's a copyright sign by nopCommerce Team
I don't think a small message should create any problem, But if you still want to remove this message, YOU CAN by paying $50 license fee, and registering your website with nopCommerce, for more info,
click here