I did this and the cost should be free. I pulled books from the library, used the computer for the children to learn Math and geography, they took Karate at church, they were in the church choir. If you coordinate with 4 other families and your local church the cost should be minimal and parents would only need to supervise one day a week. If you have a husband and wife that is only twice a month for either one of them.I don't disagree, for parents that are able to do that. My sister did that were her kids for a time and then her husband decided they could no longer afford it. My husband and I had the boys for a week that summer when she told us they were taking them out of Christian school. I was very upset and felt in my spirit it was the wrong move. But I didn't have the extra money to help them. I still feel it was the wrong move but there is nothing I can do about it. But as I said, if I had kids they would not attend public school.
I did not teach lessons. They read books and the authors were their teachers. The only exception was the geography program and math program on the computer. Moses was not a good speaker and yet God sent him to speak to Pharaoh but God also provided Aaron. Most churches with 200 or more members will have a retired teacher in the ranks. You will have a few retired people who may be interested in coming out once a week to help.