I was at Walmart doing my grocery shopping yesterday and came across a great deal on their Parent's Choice diapers. This is the brand we use and we've really been happy with them with our kids. They fit pretty well, don't leak through as much, and are so much cheaper than the name brands!
At our Walmart, they have Jumbo boxes (144 size 3 and 116 ct. size 5) for just $11 a box! That breaks down to about $.08 to $.10 a diaper! The normal sized box (70 or so size 5s) is usually $14 so this is a great deal! I'm heading back today to grab another box of each size to stock up.