How much should I charge to take care of a couple for 12 hours a week?

Depends on what you do. $25 where I live is high for a CNA. Those working in nursing facilities only make $10 to start. Is the $25 for care of both. Are you going to be bathing, toileting?

Do a google search to see what a caregiver gets paid in your area, double it and there you go.

yukii007, charging an hourly rate depends on what is the average for your area.

If the couple is mainly needing "companion" service, then $25/hour sounds good. If one or both require more hands-on care, then charging more would make sense.