The HP store does have a return policy posted. Try the "Online help" button to see the details, which include these items:
Q: Are all parts returnable?
A: No, software and manuals are non-returnable, and any opened consumables such as toner, ink cartridges, and media.
Q: Will I be charged a restocking fee?
U.S. Customers A: Yes, all good unused returns may be subject to a $25.00 or 15% restocking fee based on (Part Price + Shipping and Handling Charges). Contract customers please refer to your contract for specific details.