Is it 3500 – 4000 PER child for someone with 6 tuition aged children? What part of the US do you live? (I assume you are in the US.)
Missme your assumption that I can get an pay lower schar limud based on the number of children I have in mosdos isn’t correct.
First of all, assuming I have six kids, one of them is still a baby. Second of all, if I would only have boys it is very likely that one would already be in yeshiva or going into Yeshiva so that makes it four in one cheder. But it is highly likely that I would have daughters as well so that makes it less children in cheder as my daughters attend school. Therefore I wouldn’t qualify for a discount, unless all I only had daughters which isn’t the case.
Most people do pay between $3,500 and upwards in Chassidishe mosdos. I would assume Satmar in Brooklyn is the only mosdos that charges less.