Cars 2 is available for pre order on Amazon. The reason I recommend pre orders is because you will automatically get the lowest price that it is before shipping. If you find a better price, You can cancel your order before it ships.
This is a 5 disc combo, including Blu/Ray, 3D, and Digital Copy. The price is listed at $34.99, and there is a $7.00 Cars 2 BluRay/DVD coupon available, making this $27.99. Just clip the coupon before your purchase, it will be discounted at checkout.