My best example is Billy - Billy the pig with the cauliflower ear. He came from a huge rescue where, sadly, some of his friends had to be put to sleep due to medical reasons. Unfortunatly those pigs were too far gone to save - and it was kinder to end their suffering rather than persue the tiny remote chance of them pulling through treatment. The decision was nothing to do with finances, it was all about the pain and misery the poor things had already(and were) in.
But Billy, who was essentially a wild pig (I know, I chased him around my kitchen for a good half hour once!) came in with a horrible infected injury to his ear. Instead of passing him on to the rescues I was ferrying him between, I decided he needed to see a vet right away and he's stayed with me since. Personally I have spent £100's on his treatment, but is well worth it as he is now one of the friendliest, happiest pigs I know.
But as teadragon said, all the rescues I have worked with treat all their pigs as their own - one will always have to draw a line with piggy suffering somewhere, but if there is a chance they'll persue it, and find the means somehow. Which is why I think all the rescuers on this forum deserve our thanks a hundred times over.
It's not just money they invest in these neglected pigs, its love and heartbreak too.