Daas, it’s hard to put a “rental agreement” on the cover. “Reference” to it is insufficient. Unless the entirety of the “agreement” is visible prior to purchase, it is not binding.
If the customer opens the CD and the “agreement” says that in order to use this CD you just “rented” the purchaser is required to first dunk in the Arizal’s mikveh 7 times, is the customer unable to ever play his CD until then? If he doesn’t agree to that term (which he never saw until he opened the CD package) will the store take back the opened CD? If not, the “agreement” is not binding.