There are sooo many PSA's at the moment, I thought I would add to it!
GT6 Demo (Free) is in the PSN Store! It's actually GT Academy 2013, but is based on the engine for GT6. You get:
5 Tracks - Autum Ring Full & Short, Suzuka East, Grand Valley East, Silverstone
3 Cars - Nissan Leaf, Nissan 370Z, Nissan R35