He got to play one of those things at Johns place, and he thought it was so cool that he wanted one for himself.
He never had a gameboy, nor a gameboy-color.
He didn't want to take part in those trends, but with the gameboy-advance, it's different.
It's not about the craze, you know... that thing is simply cool.
It has nothing to do with the fact that Christopher, Paul and Tommy have one too, no, that is merely coincidence.
So, Ricky saves up all his pennies, because mommy and daddy had told him "Ok, you can have one, but you will have to pay for it by yourself, because we think it's a waste of money." Now the day had finally come that little Ricky had enough money to buy his very own gameboy-advance.