Circuit Books

One of the many ways that philatelists acquire new items is through "circuits" from local clubs or big organizations. 

In these, you would receive an envelope with some circuit books in them.  You can take what you want, write your member number in the box where the stamp was, then mark the total value taken, and mail the books to the next address listed on the circuit.  After a while, the circuit books would be retired and sent back to the member who created them with payment for the items sold.

I vaguely recall trying some of these from the American Philatelic Society back in the 90s.  The ones I made came back about a year later almost untouched, but I did enjoyed picking through the ones I received along the way.  It doesn't feel like a good way to get rid of cheaper stamps, due to time and costs.

I bought a box of these at an event recently.  Some members even had their own rubber stamps to mark the items they kept.  Those were some different times when postage on these was under $1 and we could have new batches show up in our mailboxes to pick through.