Unless you are a hardcore racing sim fan, 300 for a wheel is a bit steep - and this comes from someone who loves racing sims and owns two wheels.
It depends on what kind of racing you prefer, but for the PC I would get GTR and RFactor. The net code on RFactor is especially well done, and I've been able to game with people in the east coast (me being in Asia).
GTR2
http://www.10tacle.com/gtr-game/ is a great sim, renowned for its tire modeling. It focuses on the FIA GT series.
RFactor
http://www.rfactor.net/ is more a "foundation" for user content (mods). The stock game doesn't offer much, and what is there isn't from any real racing series, but check out this site
http://www.rfactorcentral.com/ and you can find anything from F1 to WTCC, Australian V8, various stock series from Europe, and even karting and lawnmower mods. This lets you turn it into an arcadey game as well (such as having F1 cars on a dirt oval or lawnmowers in a street circuit).
Check out this site for great PC (and console) racing reviews, mostly with a focus on simulation driving:
http://www.simracingworld.comYou can always download the demo, or in the case of RFactor, the full game (should you decide to buy it, you just do the payment and get and unlock key for the game).