According to a recent story by ProPublica and the Real Deal, in April 2016 a limited liability company managed by Trump sold two condominium apartments to a limited liability company managed by Eric Trump. They were on the 13th and 14th floors of a 14-story, full-service, doorman building at 100 Central Park South in Manhattan. This is a prime Midtown neighborhood, yet the sale price for each condo was just $350,000. Although the condition and square footage of apartments 13G and 14G are not readily known, a popular real estate website shows that G-line apartments on both the fifth and eighth floors are one-bedroom, one-bath units of just over 500 square feet. Two years before the Trump transaction, apartment 5G sold for $690,000. Maybe the two units in question were in terrible shape, but two months before the sale to Eric Trump’s LLC, they were advertised for $790,000 (on the 13th floor) and $800,000 (on the 14th floor), according to ProPublica.
[Sitting presidents can’t be prosecuted. Probably.]

If a sale between a parent and child is for fair market value, it does not trigger a gift tax. But if a parent sells two expensive condominiums to his son at a highly discounted price, for example, then the parent makes a taxable gift in part. In that case, the seller must pay a gift tax of up to 40 percent. (In this case, that might have run the president somewhere in the neighborhood of $350,000.)