So how much did Ghost Babel sell?

[SnatcherMkII]

So I got the game at a flea market despite my GBA SP is still at my friend's house, and it was originally sold for $20, but someone at the counter reduced the price by half ($10) for some reason (probably trying to get it sold immediately), even though I was saving the money for Pokemon Y, but I figured, "Sure, why not? This could be my only chance".

Anyway, since my Game Boy Advance is still at my friend's house (as I mentioned earlier), and my Super Game Boy 2 (I don't have a Super Famicom, though I did cut off the little tabs from my US Super Nintendo) obviously can't play GBC games, I just wanted to drop by and ask: how many copies of Metal Gear Ghost Babel were sold?

[TechNoir]

This site says 5-7 million copies:
http://video-games.findthebest.com/q/34 ... -were-sold

But VGChartz says only 40K, and only in Japan, lol:
http://www.vgchartz.com/game/3773/metal-gear-solid/

I don't know about GBC games' prices, but on Ebay MG Ghost Babel costs from 50$ to 100$. Is this normal? If yes, then I think Ghost Babel has sold enough copies.