Such an event happened yesterday.
I come across a copy of Gardner Dozois' The Year's Best Science Fiction, First Annual Collection at a price I could "afford" and in a condition I could live with:
Trade paperback, first printing. Fair, solid reading copy, taped along length of left edge of front cover overlapping onto spine, corners creased, spine creased and chipped at bottom.
After asking the seller a couple more questions over the phone to clarify details on the book's condition and talking with Mrs. Moose, I went ahead and ordered it. This means I will soon have a complete run of the series! Thus, the happy dance at my desk. Trust me, there's nothing sadder than watching me do a happy dance while at work. Thankfully, except for my self-esteem, no lasting damage resulted from my spastic performance.
It also means having to juggle some finances and become more active in placing some of the Phillies collection on eBay to pay for it, but it is so worth it -- and there's the added bonus that I'm paying less for it than what I sold my copy for five years ago. Of course, it's not in quite as good condition, but as I said before I can live it.
I almost forgot to add: as I looked into purchasing this copy, another one (in much better condition) was posted on eBay, and the bidding is already up to about what I paid for my copy. I have a gut feeling that one will go for far more than I was willing to pay.