Are you bonded and insured? Taken a pet first aid course? Are you an adult? Do you have any other qualifications? All these factors affect the rate you can fairly charge, as well as your location. If you're not an insured, bonded professional, look up what such people charge in your area, and divide by about three. Keep in mind that, without insurance and bonding, if anything happens to their pets or property while under your care, you are personally financially responsible for it (or your parents are, if you're a minor).