When Martelli has a 50% off sale, I buy them in huge lots. Last time I did, my two quilting neighbors and I shared them. I still have some that I have not used yet. In order to get their sales, you will need to sign up on their website and they will send you a newsletter announcing their sales. I bought my round about from them at half price too. I noted that they have a coupon redeemable only at the Houston IQF for rotary blades for any of you who plan to attend. You can either print and cut the coupon out or show them your email on your smart phone to redeem the coupon.