There is a lot of money to be saved in buying things used. Books are one thing that I am constantly buying used. We have a local bookstore that accepts books for store credit. I took in a huge box of books last year and earned a large amount of store credit. Now when I need a new good read I head over to the bookstore and use the credit to get some new books. I also used the store credit to buy my sister's Christmas present a whole series of books in like new condition. (She is thrifty like me and does not mind a used gift.)
Then there is the wonderful world of consignment sales. What a great way to buy children's clothes. These sales often sale clothes at 75-80% less than the original prices. I am especially fond of the last day of these sales which is often 1/2 price day. Getting these clothes for very low prices. If you are in TN click here for a site with some local sales. Alot of times you can search consignment sale and the state you live in to find your local sale dates and times.
Then there is always Goodwill. This is a great place to find all kinds of great deals, while doing something great for your community.
Lastly don't forget those yard sales. I love the hunt for good deals. This is one of my favorite ways to spend a Saturday. You never know what you will find.