I got really lucky...about a year ago I bought 45 packages of rotary blades on eBay...a mix of 28mm, 45mm and 60mm blades, all packs of 5, for $25.00. Since I use all three blades I figured it was a good deal, especially since most of the packages were 45mm. Since then, I've paid attention to the prices of blades and know I got a super deal on my Olfa blades!