If you mean Super Mario Bros., then go to http://vimm.net and find the rom under the NES section.  The same goes for Donkey Kong, if that's the game that you're referring to.

Go to a Plato's Closet and sell old clothes that you don't wear anymore. If you have any electronics or other things, sell those on eBay.  You'll be raking in the dough in no time!