I was wondering how everyone approaches these possible goldmines. Do you avoid them like a nasty infectious disease because used books are beneath your library's collection? Perhaps you set a limit of money spent at such an event? Limited by how much your arms can carry?
Are there some strategies you use to make sure all your bases are covered? Do you go to a specific genre table/area?
And as a final question...is there a book you have read recently which you bought at such a sale that you are so glad you decided to buy?