Moving to bangkok with wife and 4 years old kid

At 90k-baht/mo., I'd say you're all set, 3x beyond the average.

What about schooling in bangkok

Depends. Government school should cost less. An average bilingual school may cost roughly 50,000-100,000 THB. Plenty of options in Bangkok.

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That's plenty of money

Could someone suggest me name of some bilingual school in Bangkok ? I have 2 children 3y and 6y old, not speaking english. The international school is too high for my budget, while my children could not join government school. Thanks.

This is going to be your biggest challenge.  I don't know of any resolution for it, but I'll mention some related experiences.  Both of my kids attended St. Andrews British International school for their early years, but that school is expensive.  It costs around a half a million baht per year for tuition for a grade school age child (probably a bit over that), a little lower for a very young child when attendance is part-day.

My children have attended three other local schools.  One is a better government school in Bangkok Sam Yan.  It was inexpensive, even though it is well regarded (I don't remember the exact tuition, it just seemed low to me, and order of magnitude lower than St. Andrews).  My daughter also attended Sitaboon, a Chinese-Thai school, which was also relatively inexpensive.  A child would need to speak Thai to really participate in the educational process in both schools.  The third school is sort of a special case, so there's no point in getting into it.

So the question would normally become what local schools offer reasonably priced English-based education instead, but since yours speak Vietnamese even that might not be an option.  This forum is a reasonable place to be asking that question but it's a bit inactive in general.  I'd try asking in lots of different places, and using an exhaustive Google search approach as well (don't just Google "Vietnamese school Bangkok," but start with that).

Finding this website with database abt international school in BKK, including related cost. Hope it helps for other members

https://www.international-schools-datab … in/bangkok

I tried to find a Vietnamese speaking school through a basic Google search, after not seeing it on that database, but didn't turn that up.  I did read an interesting article on Filipino's not being paid as much as white teachers in schools from that:

https://www.bangkokpost.com/print/716900/

On the one hand I can see that point (beyond it just being racism), that someone from the Philippines may not be a native English speaker in the same sense, and instead of learning a British, American, or Australian accent the kids would be learning one from the Philippines.  My son has had English instructors from the Philippines and their use of English wasn't always completely clear. 

One teacher from Russia barely spoke English, although he was an English instructor in that local school, and I didn't necessarily connect that with racism (he was white), but instead realized no one could really screen them based on a clear competency level.

Then I ran across this sentence, in that article:

She added that the school does not employ African-Americans: “Not because we are racist but we are concerned that the children might be scared of them.”

As an American I'm completely not ok with that statement.  They can hire who they want but racism is racism, and that's as clear an example of it as would find its way into print.

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