Right now, you can preorder Fantastic Beasts and Where to Find Them Blu-ray/DVD Combo for only $24.99 or the DVD only for $17.96. Get FREE Super Saver shipping on orders of $35 or more (or with Amazon Prime).
The movie will be released tomorrow (3/28). The DVD/Blu-ray Combo includes the preorder price guarantee, so if the price drops before the release date, you'll pay the lowest price. Remember, if you find a better deal closer to the release date, you can always cancel your Amazon order since you're not charged until your order ships.
Be sure to check out all the Amazon deals that I've been posting for some great deals
Please note: Amazon prices tend to change quickly, so be sure to check the price before you buy.