We're sad to see you go, but you can easily cancel your subscription by clicking an in-app link.
Head to your Account Settings (the wrench icon in the upper right).
Next, select Account Settings and then Subscription from the sidebar on the left.
In the Current Subscription section, click the Cancel your subscription here link to start the cancellation process.
Please consider leaving us a note to let us know why you are canceling, and what we can do to improve ShipStation. We'd really appreciate it!