RPP stands for "Reserve Puzzle Program". It's an idea that we discussed with customers on our Friends of Cubicdissection Facebook page. The program is intended to discourage flipping puzzles on the Marketplace.
We noticed some customers were ordering multiple copies of puzzles before they sold out, then listing them at inflated prices on the next Marketplace event. This type of behavior takes a puzzle out of the hands of a collector and lines the pockets of the seller. Collectors of newly released puzzle boxes, interlocking puzzles and packing puzzles are particularly vulnerable to this type of behavior.
Under the RPP, we now hold back four copies of every puzzle that is released on Cubicdissection. We then list one copy on each of the next four Marketplace events under the username "CubicdissectionExtras".
Many times, two determined bidders competing for one puzzle will drive the price up much higher than retail. By listing the RPP copy we ensure that anyone who is ordering from us only to resell and make a profit will have to wait a minimum of one year before they can list that item with no competition.