Right now American Express is giving away free ShopRunner for life! All you have to do is enroll through this link.
ShopRunner is a service similar to Amazon Prime where you get free 2-Day shipping on most orders through their partners. This is an $89/year value (the listing price for a ShopRunner membership), so I would jump on this deal immediately!
Just sign up through the link and even if you have an existing ShopRunner account, they will grant you the lifetime membership for as long as you have an open Amex card.