I don't know what the going rate is now -- it used to be about $10 per hour, which is fair. DO take a First-Aid class, though. It does help you be more employable.
AND take a fire-safety class, if your fire department offers one. With A First-Aid card and a fire-safety card, you should be very employable in your neighborhood. Do ask the people you know at church, and never offer your services to strangers.
Never, ever go with anybody you don't know. No amount of money is worth getting kidnapped. Good luck.