The husband has stage 7 alzheimers and is total assist, The wife had a stroke and has limited use of right arm and leg but is independent. She has aphasia so I do all communication for her on the phone making appointments etc. so I speak for both of them and do all medications and all driving with my own car.
Hourly rates vary from area to area. When my Dad had caregivers a few years back, he was paying around $25 per hour for one person, he lived in a large metro area. Wouldn't be surprised if the hourly rate was now $30-$35/hr. Dad used an Agency, so they handled the payroll deductions, etc.
I wish you good luck.
Also, what is your plan for when you are sick and can't care for them (or don't want to expose them to your illness)? Or when you want time off? Are you living with them? If so, this also may not be an optimum plan for them or you.
I would work on whether the wife has a PoA. It would be important to know who this person is. As PoA for my Mom and her older sister, I can tell you that doctors and banks and investment firms are NOT going to work with only you once you cannot have the wife participate in the conversations coherently. She will need a legally assigned representative for both medical and financial and it won't be you unless you are her PoA. In the absence of this the county comes in and a judge provides a court-ordered guardian and then you will be completely out of their lives, regardless of your "history" with them.
You need to go into this arrangement with your eyes fully open so that you don't have a bad experience. Them paying you makes them your literal employer as well, unless they are paying you in cash (which may delay or disqualify them from future Medicaid assistance). Lots to think about, so I wish you much wisdom.