Estimates say that billionaire Michael Bloomberg has spent at least $650 million on various causes since his election as New York City’s mayor in 2001. The Metropolitan Museum of Art snagged $30 million. Another $7 million went to gun control, $890,000 for feeding his staff, and about $23 million in various campaign donations — just to name a few. Bloomberg also invested $73 million in his 2001 campaign, more than four times what his opponent spent. After his term expires on Tuesday night, New Yorkers may reflect on the sweeping changes Bloomberg brought, but they didn’t come cheap.