If they want to pay 'hourly' than I would charge minimum wage for your province because they are not using 'daycare' where the cost of your wage is shared between the other clients you are legally allowed to have

Personally I would not do this expect for a previous client as a 'favor' and than only if I had SPACE ~ I would not take on a new client who wants 'drop in care' and expects it to be there at their beck and call .... this kind of care is HARD on the child depending on personality and therefore the transition and behavior of the child and stress it causes would not be worth it to me ~ I like full time permanent clients or as a minimum kids who come either 2 or 3 days a week in a shared space!