This is a good article about the escalating cost of TET lucky money and gifts.
We have budgeted 20 million Dong for this year.
People simply expect extremely much from their relatives who live abroad or who are married to foreigners.
As described in the article, even the Vietnamese living abroad are hesitant to come home during the TET holidays.
https://vnexpress.net/doi-song/nguoi-vi … vn_thumb=0
But not only at TET.
Even if you travel a lot as an expat, your relatives expect to receive gifts after each trip.
At weddings, birthdays, hospital visits, etc. they also expect to receive more money than from the locals.
So those who plan to marry a Vietnamese woman with family must budget at least 50 million Dong per year for gifts.