Where can I get a Nos bottle in California?

I'm trying to find a small nitrous oxide bottle for a friend for his b-day. Are they even legal in California? If so, how can i get one? I'm looking for a VERY small bottle. Can i find one under 60 bucks? I don't care how small it is. I'm just getting it so he can have one, not use it. XD Thanks a ton guys!