You see this a lot because if 5 people all bid $1 and the sixth bids .20 the fifth spot pays .21 etc. So no matter what the top or default bid is set at, the click is charged .01 more then the spot below it. There are other factors like QualityScore and CTR but that's pretty much, IMO, how the top bids prices get pushed up much higher than the actual cost.

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