Amazon has the 8-Count of Gillette Mach3 Men's Razor Blade Refills for $19 - 5% off with Subscribe & Save (can cancel anytime) - $5 off coupon (check “Save an extra” box, eligible on first S&S order for this product) = $13 with free shipping on $35+ or with Prime. Each razor blade refill is engineered to last for 15 comfortable shaves.