Probably about half my CD collection comes from second-hand and charity shops, library sales and record fairs. There might well be some reduce-reuse-recycle point of principle at bottom here, but I do it chiefly because I enjoy the paradoxical hunt for something I'm not looking for.
Charity shops are the best places for this activity, because the professionals - Record & Tape Exchange et al - much though I love them - make it too easy to find something of interest. They're best for comfort browsing and bulk buying rather than chance, right-place/right-time finds.
Being on holiday last month was an opportunity to place myself in the path of serendipity (or at least Age Concern Lutterworth) and see what I found.
Reviews and more to follow over the course of the week.