From the eStore FAQ:
Q. How can I return an order?
A. If you are not completely satisfied with your eStore buy, you can return it within 30 days from the date you purchased it for a refund less the shipping and handling. Please contact our returns department for a Return Merchandise Authorization (RMA) toll free at (800) 468-5846. Returns without an RMA will cause a delay in processing your refund.
(Clearly it is better for the store to simply refund the difference to you, than have you return the product and purchase another at the new price).