Almost as powerful as Google Ads, the Facebook Ads platform is also free to use if you have a Facebook account and amazing for estimating market size and demand. The service lets you build what’s called an “audience” around demographics data.
So if, for example, you’re considering expanding your store that sells rock climbing gear to other cities, you could figure out which other cities have large populations of people who like rock climbing and open your new stores according to data rather than hunches or hearsay.