Those are good questions that I probably should have given more thought to before I started some of my glove projects. Finding replacement patches is tough, but your odds are better if it's for a 1940s or later glove. If you go the ebay route you might luck into a glove with a nice patch that has a lot of marker on it or a trashed liner and get it cheap. Gloves with excessive marker but in otherwise solid condition make great parts gloves. I've replaced the liners on a handful of gloves and honestly hope to never do another one. It is just too much work. First you have to find a donor close to the size of the original with the same number of eyelets and reasonably close in color, although dyeing it is an option. Then you have to carefully cut the stitching on the piping to remove the old liner and line up your replacement to fit it. Then resew that same fragile piping. I really hope I'm not discouraging you from your project, though. It is very rewarding when it is all done and it turns out nice. And I've seen many terrific restorations by other forum members. It's just that with the amount of work involved, I'd much rather patch a liner than replace one if possible. All you need to get started though, is an x-acto knife or small box cutter with razor blades, a strong needle and thread, and some leather glue. A needlenose pliers comes in handy to pull the needle through, also. I try to match the thread to the color of the piping because my stitches never come out as straight as I'd like them to be so I try to make them as invisible as possible. I always end up with one spot where the piping just won't lay flat on the inside of the glove. The glue takes care of that. Good luck!