How many copies did MapleStory sell?

799k to 1.3M copies, based on its 15k Steam reviews. This is a labeled estimate from the review count, not exact sales.

How much revenue did MapleStory make?

MapleStory is free to play, so there is no copy-sales revenue to estimate.

A labeled estimate from the public review count (adjusted for release year), not exact sales. Owner data cross-checked with SteamSpy.

We don't have enough similar games to place MapleStory in its genre yet, so these are its own numbers, not a genre read.

Sizing up your own game? See what its genre can realistically do before you build it.