As suspected the games have reverted back to their original price.
We're not sure why but a pair of Gameloft games are available for free right now on both Windows Phone 7 and 8.Earthworm Jim (WP)
$4.99/£3.99 FREE Assassin's Creed: Altaïr's Chronicles HD (WP)
I had a bit of trouble getting the free pricing to show up myself, but when I turned off my phone and started it up again, both games showed as free upon searching the marketplace. You can also use the links above to purchase the game from the web if you are having issues with your phone's marketplace showing the correct price.
As alluded to in our strapline, we don't know how long the free games will be available so get them while you can.
Special thanks to all the community members who sent this in!