Diaper and Wipes Savings At Target
Right now Target has an offer for diapers, wipes spend $100 and get a $20 gift card. This applies for same day services which includes drive up :)
This is also valid on a few other baby items as well, for example my order was a few dollars short of $100 so I added a Boogie Mist to it and qualified for the $20 gift card.
If you're a Pampers Pure lover they also have big boxes of 108 count (size 4's) for $39.99 which is substantially cheaper per diaper than the next box size down.