Technically, there is no official permanent "free" version of the full game. However, there are two legitimate "free" aspects you should know about:
With 4K support on next-gen consoles, the game features impressive lighting and day-to-night transitions. PC System Requirements NASCAR 21: Ignition Free Download
Because it is an older title, you can often find it at a significant discount rather than paying the original $59.99 retail price. Technically, there is no official permanent "free" version