I didn’t notice they’d changed from 25,000 free maps per day to 25,000 per month!
Static maps may help, since they have a 100,000 monthly free quota. Or, if your individual maps have only 1 POI, you could use the Google embed API (https://developers.google.com/maps/documentation/embed/guide) which seems to have virtually unlimited free usage.
I’m working on adding both of these options to MapPress as well. I’ll be out of the office until May 15, and it will take a few days after that.