That worked great for us. Every baby has a different shape and grows at different rates. I found that at those awkward growth stages, we stuck to prefolds and covers. When she filled out in the thighs we had great success with one size pockets. Now that she's about 22 lbs I find we lean towards fitted AIOs.
eBay, Craigslist, and Consignment
Buying on Ebay, at diaper consignment sales, and off Craigslist offered us the best prices. Locally, my favorite diaper store Top To Bottom Baby have a bi-annual diaper consignment sale called Fluff Again, they've even expanded into Kansas City. Not only could I cycle through the dud diapers and make some of my money back, but I got the chance to find fully prepped diapers I knew I liked. As long as you're willing to take the gamble, Ebay is awesome (and addictive). I know there's a lot of debate about the cheap Chinese pockets you can get on Ebay. They are knock-offs and hurt the American market. yackety shmakety- I bought about 10 of them and we STILL use about 5 of them regularly. They didn't fit right way, and they aren't the kind of diaper I'd use if we were going to be out. But they are great at home, day time diapers. On several of the other more 'respectable' brand name diapers I've purchased on Ebay, I've more than made my money back in resale.The key is responsible shipping. DON'T GUESS! Weigh your diapers and price accordingly.
Craigslist has also been a cornucopia of goodness. I got 10 Kissaluvs size 2 and 9 Kissaluvs doublers for $50. Most of them had never even been used, not even prepped.