Amazon has really great deal going on Pampers Diapers and Wipes. Currently, they are on slale up to 25% off. You can also save an additional 15% using coupon code PMPLUVJN and it is eligible for Subscribe and Save, which drops the price another 15% and gives you FREE shipping!
This drops the price of the large boxes of diapers to a little over $20. This is depending on the diapers you need.
Go here and select the one you want. Choose the Subscribe and Save option to the right. Make sure to enter the coupon code PMPLUVJN at checkout. Once your order ships, go to Your Account and click on Manage My Subscribe and Save to cancel future shipments.