Harry Potter, despite not really existing, has managed to cast a spell to lower the price of his DS game by ten dollars, to $19.99. Uh-oh, it's magic! He can only keep it up for one day, and only on one site (Amazon.com) because it takes too much strength to maintain such powerful magic, and Harry's got to get his sleep for, we don't know, a Potions test or a Quidditch match or whatever the funniest Harry Potter reference would be.
Though it would delay the shipping and nullify the release-date guarantee, we'd like to remind you that adding this to your order of Harry Potter and the Deathly Hallows would make the order eligible for free shipping. The DS game includes a children's movie ticket for the Order of the Phoenix movie as well, so if you can legitimately pass for a child (or if you are a child), you could have a triple threat of Potter media consumption in one order.