I checked with my friends.
They pay $600/month for 10 months - which makes it $6,000 a year - for a decent private secular for-profit school (no extra source of income from religious institutions). They do have busses, etc.
Other people I know friends pay only $350/month for a greek orthodox school (10-15 pupils per class) but you must be a greek orthodox (the prevalent religion among russians, BTW) to get there.
I believe that per-pupil expense in a New York public school is around $10,000 a year.
miko