Here's Kate's honeymoon dress. She was spotted wearing this when they left the day after their wedding to a secret location.
If you click on the 1st picture you will be redirected to the website of the company who has the same dress as Kate's. Apparently she is wearing a Zara dress. I can't tell if it's the same or not. But the Zara dress is very similar AND only $90. :) You can get Kate's look here for cheap, considering it's clothing of a princess. :)