You might get lucky if you ask some used video game store if they have some of those clear cart bottom covers. Some store dont care and will give them to ya. It is worth a shot.
Enjoy EarthBound for its story if you can get past the graphics and battle system.
Yeah, take note that, for whatever reason, Earthbound is supposed to resemble a circa 1992 NES game (the Japanese version even has the "8-bit" font in the selection boxes.) I have no idea what the significance of it is, though.
to get to ebay you take a left at binary road, surf about 10,000 miles at the speed of light and hang a right at the prOn palace. here. you guys can even split a lot if you wanted to be neighborly.