I do not claim to know the details, but they paid $20K and was for another non profit. It was slick but not as nefarious as you claim. In the end, they were forced to pay the additional $10K as the value of the painting was determined to be $20K by the court.
"Melania Trump and Creamer were bidding on the Trump portrait, and Creamer dropped out when the price got to $10,000; Schall convinced Melania Trump to bid against herself, "and there we were at $20,000,”
he told The Post. "Big round of applause, and everybody was excited." Melania instructed Israel assistant Jody Young to send the painting to the Trump National Golf Club Westchester in Briarcliff Manor, New York — where Fahrenthold says he suspects it may still be (the club turned away a
Post reporter).
In the end, the charity and Israel each got $10,000 of the money the Trump Foundation paid for the painting (2007 was the last year Trump put any of his own money into his foundation, according to tax records)."
Here's the story of Donald Trump's 6-foot-tall painting, paid for by his foundation