You can register item sets from any equipment box — the one beside the quest gate, or the one in your home. (kotaku.com)
Citi Price Rewind — Searches for the lowest price on registered items purchased at online merchants for 60 days. (upgradedpoints.com)
With your own, personal, Bowker - purchased ISBNs assigned to each edition of your books, they're much easier to locate because you can register each item in Bowker's Books in Print database. (midnightpublishingllc.com)