ShopRunner is a benefit I came across when ordering from Urban Decay, while checking out my order I clicked on the ShopRunner option and saw you can Enjoy free 2-day shipping and return shipping on eligible items at top online retailers.  Being a member of Urban Decay you all ready receive free shipping but signing up with ShopRunner you can get
FREE 2-day Shipping which made my order come a lot quicker.  As you can see on the image below my order change from Free shipping standard days to 2-day shipping. 

When you enroll your eligible Card you will receive complimentary ShopRunner membership, valued at $79 annually.

How can you enroll to ShopRunner?

Is simple and FREE (how is this membership which is valued at $79 annually, FREE?)
All you need is an eligible American Express Credit Card

Once I enroll, how can I use the ShopRunner membership?

Shoprunner has more than 140+ stores to choose from (Shop at participating stores)
Once you are a member, log in to Shoprunner during checkout and select Shoprunner
You should see the shipping amount change to zero (best part)

Here are a few of the many stores that you can shop and get Free membership from ShopRunner