I am a frugal girl who coupons a ton, so I am always looking for a great deal on a diaper. I have found the great deals on diapers using the following methods:
Sew Crafty Baby Customer service is amazing, shipping is FREE, and there is pretty much ALWAYS a discount promotion (most commonly a 10% off code) on the facebook page. There is also a gently used section with a lot of great finds.
Amazon - I love Amazon. If you sign up for Amazon Mom, then you get a free Amazon Prime membership, which means you get free shipping on ANYTHING you order at Amazon. Every other week I get a $5 gift card to Amazon just by using Swagbucks as my search engine. I use this to get a lot of my cloth diapering accessories, such as liners. But Amazon carries a large number of cloth diapers... I just bought a GroVia AIO on there for $8 out of pocket. I do get a small % if you buy ANYTHING from Amazon, so if you could bookmark this link and always order through it you would be doing me a great favor!
Diaper Swappers - This is a great place to find used diapers. There are some conditions that they have to help protect buyers (for example, you must be a member for a certain amount of time and you must post a certain number of posts to the forums). I love this website, it is not only a great place to snag great deals on used diapers, but it is wonderful to read the forums that cover various cloth diapering (and other baby-related) topics. I have the diaper swappers app on my phone and it is always nice to check out diaper deals while waiting at the doctor's office or when I am finding a good way to pass the time.
So happy shopping!
Check out this great article breaking down the costs of inexpensive disposables vs. cloth diapers