What is the average cost-per-hour for a care giver?

My neighbor(mid 50s) has an 85 year old mother who is having health issues and is on hospice. She needs someone to be available 24/7...not necessarily a nurse (because she refuses to take medicine) but someone who could call for help if she fell or bring her some water. My neighbor has called on me a few times and the last time i stayed with her mom while she went out for a "girls night". I was there from 6-9pm, three hours. She asked me if 15 dollars was okay becuase she "wasnt sure" what was acceptable these days (5 dollars an hour). I told her that it was fine (assuming it was a one time deal). She has since then called me and asked me to watch her mother from 8am-6pm on a saturday, i figured $50 was better than nothing, she then went on to tell me she was going to pay me $30 (for 10 hours) after i had already agreed to do it. Im not a professional care giver, but i fee like anything less that minimun wage is too little, am i correct? Five dollars seemed low but three just seems like im being taken advantage of. How should i go about letting her know i will either have to stop watching her mother for her, or she pays me more?