Lately, I have been buying a lot of books. I've had some money from birthday and graduation, and there are so many excellent books out there by such godly, intelligent people, they are worth buying. But, also lately, I've been training myself to have a more frugal mindset, and try and save money. When I find a book I want, I usually look at 3 to 4 websites before making a purchase. Those include Half.com, Amazon.com, and eBay.com. I don't usually buy books right from Amazon.com, but rather from people who sell their books through amazon. If you buy from a Half or Amazon, they usually have a standard shipping cost for any books. eBay, however, is different...people can charge whatever they want for shipping.
In addition to those, Christian Book Distributors, as well as the Westminster Theological Seminary are great on-line bookstores, with books that are marked down. If I wouldn't be saving a considerable amount ($5 or more), I prefer to buy from a Christian place as opposed to half, amazon, or ebay. WTS has a standard $5 shipping cost, no matter how much you order. CBD has an affiliate program. I was going to sign up for it, but you have to be 18 or up...come December of this year, I'm in! :)
Another great way to save money on books is to find a used bookstore. Here where I live, there is a used Christian book store, called Bright Light Books. They sell other types of books, but primarily, they are a Christian bookstore. Their prices are great, and every month a book is in, it goes down about 10%. So, books that have been there since March '06 are 50% off. Another benefit of buying from them, is you can trade books for credit or cash. They give you 33% of what they'd sell the book for in cash, or 50% trade credit. I haven't taken advantage of this yet, but while Ben is down next weekend, I plan to take some books over. Also, if they don't have a book that you want, they'll find the least expensive, quality copy they can and sell it to you. The benefit to buying it from them instead of finding a used copy yourself is you can trade for it.
God has so richly blessed His people with many godly men and women who write wonderfully, edifying books! We Christians ought to take advantage and feed ourselves as much godly literature as we can. And since we ought to do that, we ought to get ahold of them as frugally as we can!