How it works at the table
An ante is a small mandatory bet that goes into the pot before the deal, on top of the blinds. In a traditional ante structure every player at the table posts their own ante. In a Big Blind Ante structure, common in modern tournaments, the ante is collected from that hand's big blind on behalf of the table — so the collection method differs, and the exact ante amount is set by the event structure. Either way the pot starts the hand with money in it, so a relatively cheap open wins a bigger prize.