You can get a pretty decent wheel and pedal system for cheap. I would recommend the
G29 wheel and pedal set that you can easily attach to your computer desk.
Subscription is about $15 a month, but it you really get into it, they do offer anywhere from 25% to 40% discount on yearly or bi-yearly subscription.
Cars and tracks are separate DLCs which you'd also need to buy. However, for the rookie series and most of the lower class series, most of the content is already free. Also, you don't have to buy
all of the DLC to enjoy the game. Like the NASCAR CUP Series on iRacing has three cars DLC (Camry, Mustang, Camaro) you only need to buy one of the three to race in that series, same with the Xfinity and Truck series.