Right now, new members can get 50% off of a 3 month subscription. When you sign up, you're given some cars & tracks to start with. You have to buy the rest in a form of DLC. Which sounds bad at first, but you only have to pay for the extra car or track once, then it's yours forever. It is the most sosphiocated racing simulator in the world. Make no mistake, iRacing is a SIMULATOR, not a game like NTG ot Need For Speed. I highly recommend it if you're looking to race as a hobby, but can't afford thousands of dollars on a real race car. iRacing is ran by the same guys who used to make the Papyrus NASCAR games, so you know it's top-notch.
I play it on the 360. It's fun to pick up and play every now and then. I've been doing the challenges here lately, I bought the Las Vegas one and the california one, the AI cars just knock the crap out of you on those things lol. Don't really like the 2013 cars that well, kinda prefer the 2012 myself.