My in-laws (living in US, green card holders), want to gift my wife and me (US citizens) $100,000 for a down payment on a house. The money will be coming in from Taiwan. What do I need to know about this? Am I going to end up paying a gift tax? What is the smartest way for me to do this?
You're not going to pay any tax. You can receive the money with gratitude and treat your in-laws nicely.
Your in-laws will be liable for gift tax. They should be filling and filing the form 709. The end result may be, depending on their past gifts, that they will actually pay no money but instead use the lifetime exemption which is correlated with the estate tax. In other words, this gift will reduce their estate tax exemption.
If the overall wealth they expect to have by the time they die is less than $5M (+something, the current level of the estate tax exemption), this translates to having pay no tax whatsoever.
The form 709 must be filed, regardless, and a copy of it kept for future tracking purposes.