Hi M.,
I have saved quite a bit of money by going halves with cloth diapers and disposables. There are some good cloth diapers at wal-mart called Kushies (you can order them online and have them shipped site-to-store for free!), which are cloth on the inside and water proof on the outside. I got 5 of them for $30.00. I pretty much have my son wear them at home and then I put disposables on when we're out and about or when I don't feel like washing diapers for a while. I get my disposables from www.diapers.com; you buy in bulk so you don't run out fast, they are way cheaper than at the store, you can get free shipping if you spend more than $50.00 (and there are more things than diapers there too, there's diaper rash ointment, feeding supplies, etc.), and if you are a first time customer, you can type "MOTHER" into the promotions box when you check out, and you get $10.00 off your order.
Another thing I did was help a friend of mine with an in-home business by doing some paperwork for her, and I got free cleaning products as a result. She's looking for women who want to make extra money from home, and I really love her business model. The products are concentrated and you really save money with them, and they are safer than the chemicals you get at the store (I'm sure your little guy is probably into all the cupboards and stuff! These products are so safe that the FDA hasn't required them to use child proof caps!). I get their glass cleaner for $5.25, it comes with a sprayer bottle that you mix the product with water in, and it makes four windex sized spray bottles... that lasts me all year long!
Another way I save money, is by completely budgeting our grocery spending, and then we have things that we buy every time my hubby gets his paycheck. We stream right through the grocery store, get the regular items and a couple novelty items that we budgeted for, and then we DON'T buy anything on the fly. No impulse buying, nada. We've got our grocery budget down to $300.00 a month, and we keep it that way by eating healthier, no junk food, no empty calories, we make every food dollar count. :-D Buying concentrated juices that you can mix with water, buying bigger packages of meat that you can separate and re-store in your freezer, and buying good quality frozen veggies (which we steam to cook) are all ways that I save too.
Hope that all helps!