Plato's Closet is a used clothing store for young women. They usually keep high quality popular brand names in store, like American Eagle, Gap, Old Navy, Aeropostale, etc., and are also willing to pay you top dollar for the clothes you don't wear anymore. Remember, a good rule of thumb is if you haven't worn something in 2 years, you likely won't wear it again. So you can get some cash or use the cash you get to get some new clothes.
There are many other types of consignment shops, especially for children and maternity clothes that can offer you a lot for less. In addition, if you live near a large metropolitan area, check out Freepeats.org which offers free baby and maternity items for free! There are consignment shops for regular clothes too! Give a look around your area to see what is available.
Half Price Books and Hastings are two stores that offer great prices on books and other media. You can also sell your used items to these stores. If you are looking for even cheaper books on a budget, I highly recommend your public library! Its not just a place to go when you are a kid!
In addition to these, there is also your basic Goodwill, Salvation Army, etc. Every town and city is different, like the Goodwill here I know basically looks like my Grandmother's basement, which is unfortunate, so we go to other stores and options in our area. So check out what is in your area, and take advantage of what your local used, consignment, and thrift stores have to offer.
Gina, a fellow reader, reminded me about freecycle, which I sometimes forget about since I think everybody knows about it, which isn't at all true! Anyways, if you are looking for free stuff in your community that someone is also looking to get rid of, check out freecycle.org. Thanks Gina!