I don't yet have a mat
Dollar Tree sells the small self healing green mat. Get the ones with the non rounded corners and they will join up to make one big mat. I used packing tape on the back to make one large mat when I was stuck with no mat but the town had a Dollar Tree. LOL I didn't have a problem cutting over the joins at all. I noticed now there are cutting mats that are adhesive. That is something I haven't decide what good it will be but I'm sure someone will find a good purpose for them.