I would be tempted to charge her full price, and then give back the "discount" to the church as part of my offering so I get a tax receipt. You are giving her 12 days a month at $10-15 reduction, so $120-$180 a month that you are giving her. I hope she's a really good friend, that you would give her that kind of money, but in any case, that's at least $1500 a year you could get a tax receipt for if you gave that money to the church so they could pay her childcare. I just can't imagine giving one of my customers that kind of money from my own pocket. I could use that money for my own bills.