Organizations hosting an Auction have the ability to set the bid increments for their Auction items.
An item's current bid and minimum next bid can be found on the bidding page for that item. The bold number near the remaining time represents the current bid amount or the starting bid amount. Additionally, the minimum next bid is shown in the box to input your bid, it represents the lowest increment required for placing the next valid bid.
Behind the scenes, there are default ‘minimum bid increments’ that set a minimum limit on the next bid. For example, let's say the bid increments are $10 for items under $200 and the current bid of an item is $60. You’d be able to enter any bid greater than $70 (as shown in the example below).
Bid increments generally increase as the current bid of the item increases, but the nonprofit organization has final control of setting the bid increments for their Auction.