You can use any fabric. I will either order a fat quarter of the fabric collection I like from The Little Fabric Shop or pick up a package from JoAnn's. I picked up this Halloween fabric from JoAnn's and I've got plenty left to make some for friends and family (as I have time!).
For the bow, I used some glittery orange tulle and black tulle I picked up from Hobby Lobby last year.
I highly recommend checking out the tutorial. It's been a lot of fun making these and changing them out with the holidays. As an extra bonus, the removable pieces are MUCH easier to store than a full wreath!
Have a great Halloween!