The version of BD that came with DD was a limited edition, only available in certain regions. It may not be impossible to find now, but if a listing for BD somewhere doesn't specifically state that DD is included, then it will not be (the original release of that version of BD had a sticker on the box saying DD was included).
I got DD and BD when they were released, but got a few other games as a result of various topics here (either 'best RPG' posts in the chat forums, or when making suggestions or comparisons with other games). Some I missed completely when they were released, some I thought looked good when they came out, but not good enough to pay full price for, so had to be reminded of them.
