A Black Lives Matter community Facebook page has over 130,000 "likes" and uses as its cover page an illustration of an activist wearing a black hood, symbolic of the protests that erupted after 17-year-old Martin was killed by Zimmerman near his Florida home.
"I was tired of Hillary Clinton's anti-gun rhetoric," Zimmerman said of his rationale for auctioning off the pistol. "She has been stumping around for a false campaign for the Trayvon Martin Foundation. She lied, saying that I killed him when he was walking home in his daddy's neighborhood. Which if anyone watched more than seven minutes of the trial, they would know that is false."
The unarmed Martin was visiting his father's fiancee's neighborhood and was returning from a convenience store before the deadly encounter with Zimmerman, who claimed self-defense.
Zimmerman said he would use some of the proceeds to help police who were targeted by violence.
"I am going to donate to officers such as the deputy in Texas that was shot in the head at point-blank range for no other reason than he was in uniform," Zimmerman said, referring to Alden Clopton, a police officer who was shot four times ambush-style and survived.
"No one can replace his life. No one can replace the service he was doing to his community. My goal is to attempt to make his family as whole as possible again."
The gun's auctioneer did not immediately respond to ABC News' request for confirmation of the sale price.
"He is the living, breathing, walking, talking personification of injustice. He is injustice in the flesh. It nauseates us. It infuriates us. It takes us somewhere, emotionally, where we don't want to go, but we can't help it," King wrote.
This is not the first time Zimmerman has provoked outrage since being acquitted of murdering Martin. In 2015 he generated headlines for retweeting an image of Martin's corpse.