Was the Sonic Unleashed Demo free?

Neither cost money. That's why they are demos; demos are free so that you can try them out, and then then, later, actually buy the game if you like it. But, obviously, you need to have Xbox live for demos on Xbox 360, and PSN for demos on Playstation 3. And, possibly, if one comes out on the Nintendo 3ds (which is highly unlikely) you will need to use the E shop (Wi-fi).