I'll tell you about my experience mrs :)
Well I guess my other post did that, but just to be a bit boring...
My DS13 is a dealer of sorts, he is able to get all manner of things through trades on Craigslist and Ebay. When he was 10 he started the ball rolling with a trade involving his PSP...slowly he managed to get an X-box and a brand new $1000 computer.
Its hard without knowing him to understand, but he is like Authur Daley!
As part of these trades he sometimes gets the vile games. I know he plays them too, but sometimes he will just pop them back in another trade.
I think they are a bloody waste of time, but I also understand it is very much part of his 'street culture' and I'd prefer he knew about them, than was green.
That is at 13 though, they no way he would have been able to have them before 12.