Target offers up&up Baby Diapers Bulk Packs, as listed below, for $24.99 each. Add two to your cart for $49.98 to bag a $10 Target Gift Card. (It'll be automatically added to your cart.) Even better, click the 5% off subscription box on the product page before adding to cart, and the total price drops to $47.48 with free shipping. Assuming you'll spend the gift card, that drops the per-unit price to as low as $0.10/diaper. The deals, with prices after subscription discount (per-unit prices assume gift card usage):
Be sure to cancel the subscription after your order arrives, or you'll be billed for subsequent shipments.