The entire component is super easy to understand and get working, if that's your concern?
It's strength is mostly in its amazing use of the Google Maps thingy.
That's the Basic settings
That's the Advanced
And this is sticking in a New Marker, which is very similar to the demo front-end.
It is best that Daniel answers the other parts... but from the image you see the level access point for the component. So I assume this is simple enough to restrict additional Marker addings with that.
The subscription plan lasts for 365 days (1 year), and from past experience, that is way enough time for the next version to come out!
However, in the mean time the product works like a charm.
At least I think so. :=D