Eric Van Buskirk wrote an article on Search Engine Journal which detailed his data analysis of where advertisers spend their money on Google Adwords. A pretty interesting look at sectors and prices paid in certain niches.
From the article:
There is an abundance of pieces written about uber expensive Google AdWords phrases: the top 10 or 100 most expensive, for example. However, little to no data analysis looks at a more significant sample size where an advertiser spends a bit more than a Friday night dinner for two for a click.
Where I live, a nice dinner out for two would be $50. How does a dinner versus a click of the mouse from a stranger stack up for you? How’d you like to own a small business in a very highly competitive industry and run your own AdWords campaigns? Would each AdWords bid make you wince?
I analyzed the roughly 27,600 dinner-for-two-keywords– and those with higher costs– based on SEMrush data (where I work and oversee their major accounts).*