Around here, you can charge pretty much whatever people are willing to pay you! It's up to the parents to pick between what kind of childcare environment they would prefer.
If you are asking about kids coming to my home vs. me going to the childrens' home; then I would say it would be a more expensive daily or hourly rate for the provider to go to the client's home. Nannys around here definitely make more that way, but when you do home childcare you usually have more kids, so you make up for it that way.