If you bid $2 for a click and the next highest bid is $1.25, how much will you pay?
The correct answer is:
The final amount you are charged is charged for a click is your actual cost per click.
Sometimes you are charged less and sometimes even much less than your maximum cost per click.
Actual CPC is often less than max. This is because in the Google ads auction you only pay the minimum required to clear the Ad rank threshold and beat the Ad Rank of the competitor below you.