It ranges in price and quality of facilities and quality of the teachers.
There are many, many threads on this subject already on this forum. You will find a lot of good information about many schools in those threads, discussing language schools as well as those that follow the curriculum of another country. Please look through them as they have lots of good information for you!
I agree. It is pretty wide. At CAC I paid over 6 thousand dollars per semester for my daughter, (Grade 8) excluding a large non re-imbursable entrance fee. Must be about 7k now. This is possibly (I dont really know) the top end of the scale, and I suspect you can get good schooling for less.
However, I suggest that you display the country you are from, that guides more accurate answers, and also provide the details you need answers on, so dont turn it around and say "have you got kids? what ages are they" Rather say I have x kids aged y, that would prompt those in a similiar position to you to repond, now everybody will need to ask you the obvious questions, before they can determine if they can add value or not. Just seems so much more practical.
we pay 1800/month for nursery for our 2 year old, 30,000LE (5000USD) for our 3 year old and 40,000LE (6,200USD) for our 4 year old for a sub-par "international" (supposed canadian) education.
edited to add: really it depends on what kind of school you are interested in... there are language schools, "international" schools and genuine expat schools - and they range from 2000LE to 20,000USD.