I have stuck loads of stuff on for 99p that is worth more, but I have just wanted rid of it. Stupid to just put stuff in the bin though, so would rather someone else made use of it.
Some of it has gone cheaply, some of it has gone for more than i was expecting, so it works out about even, I reckon.
Not sure I have had that many bargains although these days I only seem to look for stuff that I need and want and end up just doing BIN.
I wouldn't feel guilty though if I got a bargain purchase.