Here is what I normally spend...
$20 race fee per class
$15 fuel
$6 glow plugs
Now that is a given every weekend, and I spend $40 round trip to get there.
I normally check my clutch wear after every race day. But you shouldn't have to replace shoes but 1 time a season, if you have long life shoes.
I do the same with bearings, check after every race day, but I normally don't have to replace very often.
I put in a fresh plug for every main, and use it for the next time practicing and the heats.
I use about a half gallon to 3/4 for every time out
Then you have to factor in After run oil, car cleaner, filters, ect that you won't replace, or use up all in one race day.
In other words, there is too many factors to give you a close guess, but just for shits and giggles. I would say you're looking at about $80 for an average race day