I've had a great 'beat the system' moment today. I have a used copy of 7676 Republic Gunship in which the skirt for the Asajj Ventress minifigure has been cut and so needs replacing. The cost of the skirt on Bricklink is crazy high, with the cheapest UK price being £18 (while the entire figure can be purchased for ~ £14 plus shipping - not sure why this is lower). Bricklink will tell you that this skirt is only to be found on this figure, either from 7676 or some Comic-Con exclusive.
However, I noticed that Asajj Ventress keychains were available for far less, and that these have the skirt on them.
I decided to take a risk, and bought one of these keychains for about £3 plus postage. In theory these keychain figures can't be dismantled, but in practice they dismantle quite easily when they are crushed in a vise (so long as you don't want the parts!). I crushed the innocent figure, and can happily report that the skirt survived intact, and was not irreversibly kraggled to either the torso or legs. I have another 7676 where the skirt isn't missing, so I've checked and the skirt is definitely the right part.
Saved myself more than £10 there for a single part. Small win, but feels good.