Key money deposit is you make a big deposit into a bank account, the apartment owner gets the interest and at the end of the contract you get back the principal and the landlord keeps the interest. That way you pay no rent (if the deposit is high enough) or partial rent.

From what I have read it not a deal you want to attempt yourself, in general I think you choose a place, the school pays the deposit and you then pay the rent. Some schools then charge you a nominal rent for the interest on the deposit, according to a couple of sample contracts I have seen.

The school won't pay for your kids airfares, for that reaon I am leaving mine in Guatemala with their mom and then I'll save like a, errr big saver, until I can afford to bring them all over.

From several answers I have gotten many schools are not over keen to hire people with families, if you are already in Korea with your husband though I don't imagine it would be a big problem.

Hopefully somebody with some on the ground experience can add something definite to this.