Actually as far as I can tell it's the other way around: if you embed the JS map it's free, but static tiles are charged API requests. I suspect this is because

Actually as far as I can tell it's the other way around: if you embed the JS map it's free, but static tiles are charged API requests. I suspect this is because the JS map allows Google to create onwards journeys into Google Maps, and has limited utility outside embedding maps, whereas the static map tiles could be used in all sorts of products. I could be wrong though.