I believe the recommendations was to use ipstack when I set up the GeoIP Service (it was a long time ago, so I'm not sure...and I don't see a way to check what service is used--the only setting seems to be disable it).

Is there another free service that can be used for this?

Sorry, could you please elaborate what this is in regards? We have a GEOIP service as a part of your active license but that is not an external service that can be replaced unless you're referring to something third party that you have installed which uses it.

After more research, I realize this is coming from one of my custom plugins...sorry!

No worries. Glad you found where it was coming from 👍