SEGA has been testing the free-to-play market on the 3DS in Japan, the first title that has been released is Initial D: Perfect Shift Online. SEGA has just announced a landmark for the game, reaching over 500,000 downloads on the 3DS platform.
For comparison the game only had 400,000 downloads last month, meaning that this whole month they have manage to get 100,000 downloads.
SEGA Japan will celebrate its milestone by discounting in-game purchases until November 5th. Nothing has been announced for a Western release.