cost of Masonry Wall Bracing standard

NCEES recommends Standard Practice for Bracing Masonry Walls Under Construction for the Construction Depth...

Most places I look for this book secondhand are selling it for $100 or more (amazon right now has 2 sellers, starting at nearly $170!!!)

However, if you go through more "official" outlets such as NCMA.org, masoncontractors.org, or masonryinstitute.org, the standard can be purchased for only $50... is this the same reference? am I missing something? if it's the same, why are most people selling used copies for 3x the amount of a new book?

Because they can.

It looks like it's the same book and it also looks like you don't have to be a member to buy the book, which sometimes explains the cost. Are you taking the test next Friday? It might not be worth it to get a reference so late in the game.