There are many places you can get books, and I don't pretend to know them all. I've listed a few of my favorites below. I hope they'll inspire you to make a way to read a new book or 5!
Readers make leaders!
My first recommendation is to borrow the books from the library, and purchase the ones that make a difference in your life. The ones that are listed above are ones that have made a difference in MY life, so they might not be the ones you buy. In case you want to purchase them, I've listed a few places you can buy them near you or online.
For those of us that are "too busy" to read books, my second recommendation will make it easier for you. Listen to the books, instead of reading them. As Zig Ziglar says, "Your car is your university." Insert bus/train/plane and you get the picture. That time you spend commuting you could be learning. If you listen to 30 minutes of books per day, just think of how much better versed you'll be than the person who listens to the local talking heads talk about the TV show you didn't watch last night!
Audible.com
To listen to the books, the easiest thing I've found (besides getting CDs or tapes from the library) is Audible.com ? If you don't have time to actually READ books get a subscription from Audible.com. Get the newest books, and the most interesting books here.
Simply Audio Books.com
I just found out about this from a good friend of mine, and it looks phenomenal: Rent as many audio books as you want for $19.95 a month. It's like a personal leadership library that you can get what you want, and then send it back. Netflix for audio books. What a great idea, especially if you're lacking a nearby library or bookseller.
800CEOREAD.com - A bookstore with an attitude, based here in good old Milwaukee. The "Keen Thinker" selections are worth their weight in gold, the "Jack Covert Selects" books are almost always a solid pick in my eyes.
Half Price Books - Not sure if these are in your area, but we have 4 or 5 here in Milwaukee, and often I find the books I want in perfect shape, for, you guessed it, half price! I've even found autographed copies of books here (still only half price). And if you sign up for their newsletter (they won't spam you), you'll get extra special discounts not available to the general public.
Half.com
Buy used books at Half.com for less. You might even find some for a dollar, or even ONE PENNY (plus shipping and handling, of course). I strongly encourage you look for other people's used books here, because it's simple, easy, and affordable, even with $2.49 for shipping. A bonus: link directly to eBay for the latest business book auctions.
Barnes & Noble
Why do I recommend Barnes & Noble, instead of Borders or any other chain? Because they have a preferred customer plan, where for $15 or so a year, I can get a discount on everything I buy at the store. Also, I L-O-V-E their listening stations for new music (I never buy any music from them, but that's because they think $15.98 is a fair price for a CD).
Amazon.com
Yes, I have to include Amazon.com because not only can you get new books from them, you can also buy used books, and often I find the book I couldn't find at my local library for only a dollar or two.
Your local thrift store
You can pick up some old classics at your local thrift store for just a few bucks or less if you're lucky. Befriend the people who work there, and they'll tell you what days they put new stuff out and maybe pull some of the best aside for you.
Phil Gerbyshak leads a team of people as manager of an IT Help Desk in Milwaukee, WI, and finds that sharing his knowledge is a crucial component for success as a leader and as a person. Phil's personal philosophy is paraphrased from Tim Sanders' fantastic book Love is the Killer App: "Share your knowledge, your network, and your love. The rest will follow." Feel free to contact Phil at http://makeitgreat.org or call 414.640.7445 anytime.