I checked and this is the lowest price this DVD has been listed on Amazon so far. If you already placed your preorder at Amazon, your price should adjust when you are charged.
If you want the Blu-ray version, you could preorder the Frozen Blu-ray / DVD Combo for only $22.96 (49% off). If you can’t wait and want to watch the movie right now, you can order the Frozen on Instant Video now for $19.99.
The Disney Frozen DVD will be released on 3/18/14. This DVD includes the preorder price guarantee, so if the price drops before the release date, you’ll pay the lowest price. Also if you happen to find a better deal closer to the release date, you can always cancel your Amazon order. You are not charged for your order until it ships. So ordering now is a win/win.