Over the weekend, Amazon dropped the price of numerous Blu-ray 3D combo packs (that typically also include the Blu-ray 2D, DVD and digital copy versions as well) down from between $25 to $30 all the way to $14.99. That is usually the price for a 2D versions of a Blu-ray, so you're basically getting the 3D versions for free.
I cannot find a page on Amazon.com dedicated to this Blu-ray 3D pre-Black Friday sale so I did some prowling around their site to see what's out there. Here's a list of Blu-ray 3D combo pack titles I found that are currently priced at $14.99. Each links directly to their purchasing page at Amazon.com. Unfortunately Amazon is offering no indication of how long this sale will be running for.
You will notice a lack of Disney and Marvel titles in that list. Those infrequently are discounted, but we will definitely pass along any news of lower prices should they come along.
Browse all Amazon.com Blu-ray pre-orders