Similar to previous Ink Station Shop-a-Docket deals.
These codes gives you 15% off compatible cartridges (i.e. not OEM cartridges). You get free shipping if the price after discount is over $50.
The usual disclaimer about using compatible cartridges, but I have ordered from these guys a number of times before.
Different codes expire on different days (up until Jan 12 2017), so try a different code if the one you used wasn't accepted.