AutoX is too expensive???? Why do you think it is too expensive? Here in KC it is about 30.00 for entry fees. plus what ever food and water you bring. Just go out and run your car in what ever class you fall in, and don't worry about having your car prepped 100% the first couple years is mostly learning any ways. See if your local region has a street tire class. BUT PLEASE for the love of God, don't kill yourself or some one else on the public roads (it sounds like you have already learned this lesson).
Most regions even have loaner helmets.
It looks like you are near LA, they run autoX's damn near year round out there.
http://www.solo2.com/And here is there forumhttp://forums.solo2.com/
I am sure you could find out there what / where the closest events are to you.
Good luck, and keep it smart on the streets.