I don't usually endorse programs or products but I LOVE the Amazon Mom "subscribe and save" program. If you've never heard about it you can check it out here. Basically you setup a reoccurring order for anything baby related (diapers, wipes, powder, shampoo, etc) and specify how often to deliver (once a month, every other month...) Amazon gives a 15%-20% discount on the supplies and ships them free of charge. I've found the prices to be better than Costco's, plus it saves a lot of space in my shopping cart for actual groceries.
That's my "two-cents worth" for today. (or for this month. considering how often I actually post here)