Hi,
I have my NES console Entrainement but the problem is I only have two games(Kirby and Super Mario/Duck Hunt) so I want to like buy a cassete on Ebay cheap and insert another games on it are better insert a lot of games on it. I really dont know if it possible. Thanks for the help

 

I believe there is an entire black market for bootlegged game cartridges. And you can also emulate the NES in software and use ROMs you download off the internet.

These topics skirt the Terms of Service here, to the degree that these activities are often done to get around copyrights.