In WA, when they were still using Boeing it was $25 if you pre-registered, and $30 if you just showed up. Generally you'd get 4 runs, occasionally 3. Rarely did you get more than 4, and out of the 15 or so that I went to, they did fun runs once. Fun runs were $1 per extra run after everything was all done. But now the Boeing site isn't used anymore, and the only two sites they use are too far for me to justify going. An hour or more driving with a ferry ride, or 4 hours east. No thanks.
I want to get into track days at the local track, but normally to qualify for those you have to enter a driving school. The one run at the track is $525 for a one day school before you can run lapping days. Plus you have to pay extra money on your first lapping day because an instructor has to ride with you all day.