I have to side with Hayden here, I think you're better off with a controller rather than a cheap wheel. The wheel initial does make the game harder, but after I got used to it it's awesome how much more precises you can be with steering, throttle, and brake inputs. The better wheels w. good Force Feedback really give you a sense of weight with the car and it's super easy to FEEL when the car is getting light, pushing, etc. And having a good set of pedals gives you that ability to threshold brake, heel/toe, and manipulate the throttle well.
Sometimes you can get used G25/27's online at reasonable prices, otherwise if you can find someone with a discount direct through Logitech a brand new g27 is like $180-200.