IndieMap

$1 is pretty low barrier to entry, but like @Cedric said, might not work great in small areas.

very alike a game, remind me of meta universe...

Is this useful for people who live in big cities? Seems like there'd be a lot of pins in a small area...

Interesting idea, I think this could work very well in smaller cities.

This is actually pretty cool. Feels like the kind of thing you open just to explore who is building what.