There are guys in my series who race until their Visa can't hold anymore, and then their season is done and they go into "pay it off" mode. lol
With us, we budget for it. It is our entertainment budget for the year (we don't party, drink, go on vacation lol). It's VERY expensive (probably $10,000+ a year), but it is a fun time and it's something we do together. It could be done cheaper, but we like to have a nicer car with nice gear on it. There are guys there who actually drive their cars to the track and race, then drive home. Little $3000 CRX's that only require you to put gas in them and change the oil every so often. So much cheaper, but the class we run in, all of the cars are much better prepared, faster, modded, etc, instead of running in stock type classes.
Discounts help, friends volunteer to crew for us, and a lot of our own time goes into labour. In the end, it is worth it.
This year, we're thinking of the new engine as an investment in saving money from switching to pump gas. Race fuel was at least $1200/year.
Other costs:
Tires (at a discounted rate from a broker - slicks): $1500/year
Entry fees: $1550/year
Licenses: $340/year
Other misc. fluids, etc: $500/year (High end racing fluids (royal purple, redline, etc), amsoil premix)
Brakes: $250/year
Camping: $500/year
Gas for tow vehicle, gas for race car
And we do about $5000 worth of work or more each winter updating, upgrading and rebuilding.
