I am currently a private chef for a family of three, which sometimes goes up to 5 people. They are elderly people visiting from Austria and require high quality but simple to eat meals. I do all of the grocery shopping and cooking which takes about 6 hours a day. I then serve them dinner and clean all the dishes as well. I drive a half hour to their lake house each day which costs me around $25-30 in gas money. I occasionally serve lunch meals and chauffer them to the places they need to be. I am unsure how much to ask for payment because they are relative of a family friend. I am lenient on price however I do put in very many hours of driving, labor, and doing extra work such as looking after the family.
My question is what are the usual rates and if I should pay by hour+ gas, by meal+ gas, or salary?