It shouldn't matter how expensive the gifts were. It was rude to turn around the next day and give them away. Mike may not be a prize, but Natalie is way worse. She is crazy. If my husband gave away all the gifts I got him the next morning I would be raging mad.
Mike does provide her with more than just food. A place to live, utilities, a truck, clothes, medical insurance, surgeries, etc. Yes, he signed up for that. But for her to make the comment he just buys her food until she gets her work permit isn't exactly true.