Using a coupon code is a GREAT way to offer your books to organizations, contributors, and friends and family at a discounted rate. It is simple to set up, and quite rewarding to use. Why? Your royalties are far higher on your CreateSpace estore than they are if someone purchases through Amazon. So even with a discount, you stand to benefit greatly. Especially if you are hooked in with an organization that will buy your book in bulk.
Check out this simple tutorial on creating your estore coupon code.