Sorry this is a known issue - basically Google Maps are being included even if you didn’t provide an API key. Here is the open bug report: https://www.drupal.org/project/farm/issues/3066192
I actually have this fixed in my branch that integrates the new farmOS-map library (see Starting work on farmOS-map library), but it’s not ready for use yet.
Do I need an API key, and if so how likely am I to use more than $200 worth of requests?
For an individual farm, I can almost guarantee that you will not exceed Google’s free tier limits for requests. Currently I’m sharing a single API key among all the hosted farmOS instances on Farmier, and I haven’t been charged anything yet. However, I was also grandfathered in from before they started charging, so I’m not sure if that’s a factor. Still - I think the free tier limits are probably a LOT more than an individual farm will ever use.