Price Search for 3D: eBay $48+, Zavvi $26.99 + $4.99 S/H = $31.98, Amazon France EUR 33,49, ~ $37.45.
Toy Story 4 will be released in 3D Blu-ray worldwide except in America where it will only be released in 2D, so if you are interested in 3D, you will have to import it e.g. from the UK, Germany or anywhere else in Europe or Asia.
Amazon UK has both 3D and Blu-ray on sale for pre-order today. If you have a credit card that doesn’t charge a foreign transaction fee, use that card to place your order. If the price drops more until release date, you will pay the lowest price.