Living with others & babysitting

Living with others & babysitting

I was given a proposal from some people I know to live in their home and help them care for their children and the home. I have a 3 month old daughter and I love the idea of staying home with my daughter and this may be the opportunity. So, my question is if I am living with them (my daughter and I will share the upstairs of their home which is one large room) and I am helping them with the kids and the house what should my share of the bills be? The wife does not have a job but she is looking for one. I will only watch the kids when they are both gone I assume. The house is kinda a mess at this point and I would also help keep it all organized. The house is not very big but definitely better than my current situation. I could get my own place for about $500/month including utilities and do at home daycare. OR I could take them up in my offer but they are asking me what I think is fair. To be honest I have NO CLUE. Any ideas?
my apartment!

my apartment!

Crocus…

Crocus…

. . . and growing and growing and growing. . .

. . . and growing and growing and growing. . .

Mushrooms

Mushrooms

Flowering bush ID

Flowering bush ID

my soon to be apartment!

my soon to be apartment!