http://www.lacity.org/finance
http://www.culvercity.org
County requires filing of DBA:
http://lavote.net/clerk/naming
fee is $23 to file and $50+ to publish in newspaper for four weeks.
http://www.filedba.com is the cheapest that i found
CA State Board of Equalization permit required to sell any tangible
goods (so you can collect sales tax)
If you incorporated, then there is a whole other set of stuff you need to get. But since I'm not incorporating right now, I'm saving that legal fun for later.