One of the top ways I saved money this last year was to use cloth diapers. JW is now one and we have only purchased disposables once. We were taking a long trip to visit family and I did not want to inconvenience them by needing their washer.
I know the initial purchase of cloth diapers can be very intimidating. There are many brands to choose from and buying a large lot can be very costly. I personally use fuzzibunz perfect size. I have purchased all of our diapers used and have found great deals on large lots of each size. We have a total of 70 diapers ranging from size small to large and I have paid around $2.00 a diaper(pocket diaper +2 inserts) by buying them from local consignment sales and sites like eBay. Check out this savings calculator for the first year after initial purchase of cloth diapers with a first child and this savings calculator for use with a second child.
Along with buying my cloth diaper stash used I also saved money by buying my wet bags on clearance because they were considered seconds. Many times you can get excellent discounts and the products only have minor flaws such as uneven stitching. I also save money by making my own cloth diaper safe laundry detergent using equal parts Borax and Washing Soda. Instead of purchasing cloth wipes and specialty sprays I use infant wash clothes that I have received over the years and I make my own wipe solution. All it takes is a spray bottle (I purchased mine for $1), water, and several drops of infant wash or shampoo.
My advice when choosing to make the switch from disposables to cloth diapers is to research all the brands until you find the style that will suit your family best. Talk with other moms that cloth diaper. Read the reviews on cloth diaper sites and understand the pros and cons of each brand and/or style before committing to a large purchase. And lastly take your time and look for deals. If you are not comfortable buying used diapers there are still lots of sites and stores that sell discounted new merchandise.