It is a good thing that a Bundle of Holding is so big, because it takes a lot of space to hold Monte Cook's Ptolus: City By The Spire. Arguably the biggest single shot setting for gaming (I don't really consider World's Largest Dungeon a setting), Ptolus comes in at more than 800 pages. For $19.95 you get the core book AND all of the following: the Chaostech supplement, the Banewardens and Night of Dissolution adventures, the first issue of the Ptolus comic and a couple of character journals.
With the new edition of D&D rolling out, a lot of people are looking for settings for their games. Why not go for Ptolus? The conversion between 3rd and 5th editions look to be fairly minimal and you get a top flight setting that embraces the paradigms of 5th edition D&D, primarily exploration.
You should get all of the setting you will need for a hundred campaigns out of this book.
If you want to level up for the bonus material (which while cool isn't as compatible with the 5th edition rules), you only need to pay a few more dollars ($26.53 at the time of this post) you can also get the Complete Book of Eldritch Might, Books of Experimental Might I and II and Books of Hallowed Might I and II. You will also receive another adventure that you can adapt to your 5th edition games (Dark Tidings) and Secrets of the Delver's Guild, a series of articles originally written by Monte Cook to explore the world of Ptolus.
So, for less than the cost of a copy of the Player's Handbook you can purchase the last setting that you may ever need and use it for your 5th edition games.
This Bundle expires on September 16, 2014.