Sorry, I misunderstood. I thought you had just made the purchase.
Something you can do is write to the manufacturer and ask about the proper care of your mat. Fiskars told me to "roll" the mat to open the cuts and use a brush to brush out the lint from fabric. Elsewhere I read that using dull blades and putting too much pressure on the cutter, can and will make deep grooves in the mat. This can be remedied only by changing blades. I found I was tightening the nut on my rotary cutter too tight, and the blade did not roll freely. Another hint...you can use the other side of your mat since it is the same material all the way through. Get double your usage if you don't use the lines on the mat for measuring.
Then, if you want a good buy on rotary cutter blades, here is an idea:
http://www.houseofhanson.com/lpsharp.html
I have used this service. I sent 10 old blades and got 10 new OLFA blades (not resharpened blades as they were in sealed packages) I bought mine about a year ago and paid $27 for 10 45" blades. I think the price has gone up. But still, as sharp as those blades are, I was afraid to throw them out in the trash, so saving them in a container proved to be a good idea.
June