Kids stuff is expensive, especially since they outgrow their clothing and get bored with toys so quickly. Even if you don't have children you can find some great things on Craigslist and Freecycle.
It doesn't cost anything to be on either of the websites and you can browse what other people have posted or even put up a request for something specific.
Craigslist has been a great way to buy and sell things for Garrett and even myself. When he was done with his baby swing we sold it and made some money to stick in his college fund. I found a great Little Tikes play castle being sold for $20. They can retail for $80 or more. Besides their for sale section they have a Free section. I've scored a brand new pair of Havanias flip flops that retail for about $20.
If you're more adventurous you can check out the barter section and barter with people to exchange items and services (such as landscaping, plumping or graphic design).
The there's Freecycle. We ended up with some many things we know other people could use but wouldn't really want to pay for. I got so many samples of formula even though I was breast feeding. Through Freecycle I was able to donate them to someone who needed it. You can automatically post your "OFFER" and see if people are interested or wait until someone makes a "WANTED" post asking for a specific item. You'd be really surprised what you can get through Freecycle. Someone posted an offer for a frog pod for the bathroom, I jumped on it and it's great for storing tub toys.
When I needed a scrap book I posted looking for one and was surprised that several people were willing to give me one.
You'll be surprised at what other people in your community are willing to give you for little or no money. And when you're done with an item you can pass it on to others.