I see most authors here provide a google map shortcode with their themes. AFAIK , google requires you to use new API keys for every domain. So do you guys make an input for the buyers to enter their API keys?
Yes. A simple option text field that the user can copy paste their API into does the job fine.
google maps API v3 no longer needs API keys
I can’t remember off the top of my head how it’s done but there is a way to cheat and not use the API by using an iframe and the url of the map.
You could also use one of the other map options.