Its not pretty, im not good at this, but that just means everyone can do it!
Made from a 29*2.4 tube, cut open, folded, sewen, turned inside out, applied velcro to close it and one strip to wrap around my saddle.rails and the bag itself.
Should be cheap even if you have to buy the velcro, but I had it lying around.
I made it because in less than 1,5 years I destroyed 4 bags. All because their zippers broke from moisture, mud and use. I also tried a burrito bag, but that was annoying to access and is really bulky.
by meglemel