It all depends at what level you are talking about.

And to start this off right no one can just jump in a car and really go "Road Racing". All the sanctioning bodies have a program where you are checked off to go out on the track with other drives... and be actually "Racing".

So lets look at the very beginner. You have a safe car and want to experiance driving at both your limits and the cars limits. Well for $20 you get to run at local autocross with 4 runs and about 2-4 min seat time. Well if your funds so allow you can take that same car, change you brake pads and for $500 you get speeds of over 100mph, and about 2 hours of instructed track time. So $20 for 4 min AutoX = $5 min $500 for 120min (includes food and hotel) = 4.16 per min!!!

I look at it like this if I run 3-4 Track days a year I will use up:
$200 in tires
$100 in brake pads and rotors

If I go to 2 National SCCA Solo2 events I will use up:
$600 in tires (a new set for each event)
$100 in Brake pads and rotors

And if you add up all the entry fees I paid out in the past 2 years it would had up to about 4 track days.

IMO do them both!!!!

It looks like in '07 we will be building another car just for the track. It will have a very basic set up in what ever platform we decied to run. I figure a 94 or 95 integra, replace the bushings, suspension, gut it and add a role bar for the first year and then do FD and LSD or even a ITR swap and play away!!!! (The CRX just looks too nice now that its back from paint to whore it out on the track)