I always shake my head at this topic. Patch kits are so cheap compared to the cost of not riding
Having said that and while agreeing with Stuart's posts most of the time I will say that one can make their own patches from pieces of old inner tubes. The piece needs to be dealt with just like the tube prep before applying a patch. Cleaning, applying glue and letting it dry. I've done this a few times over the years, mostly to show it can be done as the prepared "patch" won't like being stored or packed away for future use. The "patch" will have a step of thickness along it's edge that will more easily roll up in use. Think of the cheapest old time patch kit patches and add more crudeness. It takes more time and glue. So whay one would do it as the regular method is beyond me. But I guess when you're at the side of the Silk Road and have run out of good tubes and patches yet still have lots of glue and time this would get you up and riding for a while. Andy