The top of page bid estimate is the approximate cost-per-click bid you would need to make for your ad to show at the top of the first page of the search results for a given keyword search.. Your ad can still appear if you bid does not meet the estimate, it is just less likely to appear the top position. It is also not a guarantee that the ad will be shown at the top position.
PPC Management Agency Google Adwords Metrics Top of page bid estimate
