Welcome from Ontario, Canada. Bring your rotary cutter to the fabric store or Walmart and see what blades will fit it. I use the 45 Olfa cutter for most of my cutting and you will need a rotary ruler and cutting mat to go with it. Sometimes you can find a package deal for a new quilter that has the mat and cutter bundled in a package at usually a better price. If you are in the U.S. as someone else mentioned use a Joann's coupon if possible.