Since I recently got back into Trek-Lit after a 10-15 year absence, I've been hitting a lot of used book stores looking for copies of the great books I missed. Most stores are overflowing with the numbered series from the 90s, but occasionally you find some gems.
While working out of town this week, I found a copy of A Stitch In Time, which I never thought I would find. Great shape for only $3
A couple of weeks ago I found a huge stash of books, still in perfect condition, for only $1 each. Lots of titles from the DS9 relaunch and Titan series. I grabbed 28 in all, some just because they were in better shape than what I already have.