How much do I pay my mom??

I started working last week Monday-Friday 8-5 my mom is watching my 3 and 1 year old for me. I want to give her money for that but I’m not sure how much to give her a week! I’m helping with a bit of snacks, fruits, milk, eggs, stuff like that but I still want to pay her cash because they’re a handful. Can someone help me?? She doesn’t tell me how much she thinks it’s ok either she just tells me I don’t have to but if I really want to give her something I can give her whatever i want i just don’t want to give her too little lol