The great thing about the premise is that the kids didn't actually have to pay for any of the cards. They just rained from the skies like manna from Heaven.
Not only does this anime support socialism, but it also gives divine justification for it.
It also solves all the moral and ethical ambiguities found with Pokemon etc.
WELL THE CARDS ARE MAGIC AND THEY CAME FROM NOWHERE. THEY JUST SHOWED UP SO THERE'S NO REAL MORAL PROBLEM WITH TAKING THEM FROM EACH OTHER BECAUSE THEY DON'T REALLY BELONG TO ANYONE.
I remember trying to watch this at 5:30 in the morning after coming off of a Vodka and Orange Juice bender. I sobered up real quick. I believe I also vomited.