It's easy to get a loan that's bigger than the $300 limit via the internet in California. I know, I did it several times. That doesn't mean these loans are legal, however.
Go to the Dept of Corporations website (click California.gov to get there). Check to see if these loan places have a license in the state. If they don't, they are illegal and all we advocate paying back is the principal (what you actually borrowed, minus the interest). If they give you grief, and they probably will, immediately file a report with the Dept of Corporations.