Slightly off topic, but I'm from Europe, and when you are saying "you get $15 an hour", do you include taxes or not and how much taxes do you have there?
The median rule of hourly earnings to yearly earnings is 40 hours/week and 50 weeks/year, which results in every $1/hour == $2000/year in earnings.
For $15/hour, that's about $30,000. For a single person in California, without dependents and claiming themselves for one exemption, it would be 4,264.50 (14.22%) in Federal taxes and 579.35 (1.93%) in State taxes for a total of 4,843.85 (16.15%) in taxes.
Calculator: https://www.tax-brackets.org/californiataxtable
So after taxes around $13.40 to $13.70 per hour.