Spend $49 at Diapers.com (1 800 Diapers): Pampers and Huggies Baby Diapers, Enfamil and Similac Baby Formula Delivered to your Door - Buy Baby Products at Diapers.com (1 800 Diapers) get $10 off and free 2 day shipping. Plus no sales tax unless you live in PA, NY & NJ!!! Use coupon code: RAMX3779
Cost per diaper is pretty competitive, and they also take manufacturer coupons (you have to mail them in prior to placing your order). They carry more than just diapers too.