September 18th is the prerelease for Zendikar Rising, the latest set for Magic the Gathering. On that day you can get your Booster Boxes and Prerelease packs.
September 25th is Release Day, you can get your Bundles, Collector Packs and Set Boosters.
Note: Set boosters are so heavily allocated that we will not be offering a box discount. Packs will be $6 each.