My check engine light came on....?

I thing someone LIED. California has too many problems to p such a law. That said, what year is your car? If it is pre-1996, it probably uses OBD-I, and you can pick up a manufacturer specific code reader for about $20,00 nearly anywhere, If it is 1996 or newer, it uses OBD-II, and you can find a code reader, for around $50.00 at almost any auto parts store. If you what a true scanner, you will pay at least $100.00, and as much as $500.00. Unless you will use it often, you are better off paying someone to read the code.