when i started collecting games about 8 years ago MM cost 1750 euro about 2100usd and MB about 1500 euro about 1800usd
the guy had 6 games, i didn't bought them because i didn't liked the game and i could buy Totan and CV for 1200 and 1400 usd so i did not see why i should pay more for those other titles
even 2 years ago MM was 3500 usd for me and still i let them, but the last 1.5 years it went up like hell
in France we have prices from 8000usd now for a used MM
but since the MMR a lot of people start selling these games, only last week 6 MM's were available on a French forum, and normally we see about 3 a year so i think the bubble is collapsing slowly