It wasn't OUR TAX MONEY. HE RELEASED the funds. Don't bother trying to learn the truth, it doesn't support your opinions.
$400 Million (Principal): This was money originally deposited by Iran's Shah in a U.S. Foreign Military Sales trust fund in the 1970s to purchase U.S. military equipment. When the revolution occurred in 1979, the equipment was never delivered, and the funds were frozen.
$1.3 Billion (Interest): This amount was negotiated and paid to settle interest on the $400 million principal, which had been held in a legal dispute for 35 years at the Iran-U.S. Claims Tribunal in The Hague