Have you ever played a game where everyone bids on something and the person with the highest bid wins? Well, a unique bid auction is a bit different. In this game, everyone still bids, but the person with the lowest unique bid wins!
Imagine you and your friends are bidding on a toy. You each write down the amount of money you are willing to pay for the toy, and then you compare your bids. If two or more people bid the same amount, those bids don't count. The person with the lowest bid that nobody else wrote down wins the toy!
For example, if you bid $5 and nobody else bid $5 or less, you win the toy! But if two people bid $4, nobody wins because the bids weren't unique.
In a unique bid auction, it's important to not only bid low, but also to think about what other people might bid. If everyone else is bidding really low, it might be better to bid a little higher to increase your chances of having a unique bid.
So, in summary, a unique bid auction is a game where the person with the lowest bid that nobody else wrote down wins the prize!