The 15 pack of Mach3’s is a slightly better deal over the 10 pack. I was able to purchase the 15 pack for $23.23 – 6% CB using this deal. ($1.55 / blade plus 6% CB.)For those comparing the different style blades and having difficultly with skin irritation…I have thick, fairly course facial hair and shave daily. I’ve tried the fusion and other 5 blade designs over the years, but they end up irritating / burning my skin after the first couple of shaves. Mach3 regular (non-sensitive) works better for me but YMMV. Also these razor blades should last weeks not days. You should not need to replace blades every 2 or 3 days. If you are replacing blades that often, try a different technique. I.e. Shave in a warm shower and use a surfactant like shampoo or a gentle soap as a pre-shave lather. After shaving, rinse the blades and shake the water off after every use to help prevent rust.I get 3 to 5 weeks use per Mach3 blade. Warmer water and more lather toward the end of blade life. If I go two days without shaving, I need a newer/sharper blade or to make a light initial pass with the hair grain before coming back for a close shave against the grain.To get the discount to show up on the 15 pack I had to:1.) Navigate to the 30% off S&S eligibility link mentioned toward the end of the original post. (Link)2.) Changed the drop down on the Mach3 listing to 15 pack and added to cart.3.) Went through checkout and changed delivery day for extra 6%.$35.75 – $1.79 S&S – $10.73 Coupon Savings > $23.23. Delayed delivery to next week amazon delivery day for an additional 6% CB.