I use the velcro disks and for the velcro I just went to a local fabric shop. Most carry the sticky backed velcro 2" wide and you buy it by the foot. Get the hook velcro for the pad and you can get the loop for sheet sandpaper if you want. At the last wood show I was at I got sandpaper by the sheet with the backing already on it so I cut the disks out of it and apply them to the pad. I think the hook velcro was $1 per foot which gives me 6, 2" disks. Been using this for over a year now with no signs of wear on the velcro but when it does wear out I'll just peel it off and put another piece on. For pads I just use the rubber floor matting designed for kids play areas. I have pieces of it in front of every tool in the shop along with some extra so it was cheap and easy to cut.
Rick
I support the Pens for Canadian Peacekeepers project