Let's say I am letting out a room in my house on AirBnB for $100 per night. Then one day a relative of mine is down on his luck, so I take it off the market and instead let him stay in that room. I don't charge him anything. There is no formal agreement. The arrangement last for many months.
Is my gift of sleeping accommodation liable for gift tax? How is the value of it assessed?
How about if I let him use my car?
A key thing here is that what I am "giving" him cannot be resold. If I give him a house or a car he could then resell that, but if I let him stay in my house he can't sell that to someone else.
Is it different if he is not a relative? How is it different if he is my spouse?