Dont know your mat size but here is a free pattern.
Red

Here is a link that might be useful: cutting mat carrier

here is one to buy!
Red

Here is a link that might be useful: carrier

Thanks redpenny! That was just what I was looking for...pattern and general directions . And so fast.
Always, the best place to start looking for information is right here on the forum......Marge

I just bought my daughter a mat, ruler, cutter and a few extra fancy cutter wheels for Christmas. A great way to keep it all together.. I am going out and find some fabric to make one. I think I will put a few snaps at the top to close. Maybe make it out of some demin. She would like that.. I can see different size pockets on each side . She will love it that Ole Mom made it..

Susie

I was going to show a pic of one I made a few years ago when I was going to a quilt guild but couldn't come up with the pattern. It is simular to the one posted by Red but has a few more pockets. I did mine in pre-quilted fabric on the out side and cordinating fabric on the inside. It folds in half with handles. It was useful to travel with. Jayne

I just made a tote a few inches larger than my mat. I used the nylon window screening to make zippered pockets to hold stuff in. I'll try to get a picture and post it in the next couple of days.
Carolyn

I hope this pic will work. I used nylon window screening to make see-thru pockets, compartments and zippered pockets. I just measured my mat and made it a few inches larger.

Here is a link that might be useful:

I made one using the Fons & Porters pattern in the Summer 2008 Easy Quilts magazine. There is a kit available on their site but I used my own fabric. It was very easy.

Here is a link that might be useful: F&P Kit