Whiskey I got about a week and a half ago, his fins were covered in small holes, he had fin rot, sticky fins, had lost a lot of color and was barely moving in his filthy cup. Now he is a whole new fish.
I will rescue bettas that are in really bad shape, sometimes stores will let me have them for free or discounted other times I do pay for them. I nurse them back to health and then adopt them out to new homes! I've been doing it for over a year now. It doesn't make me money or anything, since there are no adoption fees, but it is sooooo worth it!