I thought I'd add that I found that using the coupon code was pretty non-intuitive.
There isn't any immediately obvious place to enter it at the start. It turns out that you don't actually enter it until the very end, many screens into the purchase process, and I kept thinking that I was going to end up buying the bundle at "full bundle" price.
But, it there IS a place to enter it and it DOES work eventually - but not until after you go through the whole PayPal process and get sent back to the main website.
There are instructions on how to use it here:
http://ebooksdirect.dianeduane.com/p...discount-codes
and you just have to have faith that eventually you'll get to enter it