What does increments mean?

Answer 1

Starting bid is the least amount of money they'll accept for an item, and bid increment is the amount it goes up with each bidder. For example: Starting bid is $10, and goes up by $5 increments: $15, then $20, etc.

Answer 2

For something to happen in increments or for it to happen incrementally means that it happens in small and discrete steps, and the implication is that the steps are in order. It can refer to a process that involves an increasing or decreasing amount of something.