I need help
are the schools expensive in Riyadh ? Is 22,000 sr per year enough for American curriculum schools?

If you're looking for an accredited school following the common core standards etc, then no. That will definitely not be enough. You may find a school with English language instruction in math, English, science, social studies catering to locals.

Be aware that a school like this will spend a lot of time in the day doing Islamic studies, and all the kids will speak Arabic all the time. Is that's what you want that's fine, but if your kids don't speak Arabic it could be an absolute nightmare for them and a massive adjustment.

Have a look at M.I.E.S Riyadh maybe, They're at the cheaper end of the scale, but like I said, it will be catering to locals.