If you’re serious about containing costs, form a gentleman’s agreement to limit yourself in certain areas and take it to the rules committee to be codified. National level karting is cool, and I sometimes envy those who do it, but I have no sympathy for the costs involved — they are all self-imposed.
I probably shouldn’t even chime in here, but hey, it’s a free country…. :) If I ever make it to the National level, look for the SUV with the flatbed trailer. :)