Something to think of...Amazon Mom. One of the best perks, up to a year of Amazon Prime for free!! Plus discounts on diapers up to 30% off using subscribe and save (looks similar to what diapers.com offers in the way of discounts). I was just looking at Pampers Swaddlers Size 1, and a box of 216 diapers goes from $40.20 to $28.14 with the S&S discount.

Amazon Mom

Here is the info from amazon's site for the Prime and the S&S:
Prime Shipping Benefit
Amazon Mom members receive up to a year of free Amazon Prime shipping benefits. Your first three months are free, and for each $25 you spend on products in the Baby Store, within a single order, we'll grant you an additional month of Amazon Prime shipping benefits. To determine whether your purchase qualifies, we will total the prices of the items in your order as displayed in your Shopping Cart (i.e., not including any sales tax, shipping or gift wrapping charges and prior to the application of any promotional discounts on the detail page, such as coupons and the Subscribe & Save discount). You can earn up to one year of free shipping benefits from the date you joined Amazon Mom. You will be credited when qualifying items in your order ship. To track your progress, visit the Manage Prime Membership page in Your Account.
Subscribe & Save Items
Amazon Mom members receive an additional 15% discount on top of the standard 15% discount on select diapers & wipes with Subscribe & Save delivery, bringing the total discount to 30%. Visit the Manage Your Subscribe & Save Items page to change delivery schedules, quantities, and more.