Way back in the day when Square Enix was known simply as Squaresoft and only made great games, they decided late in the process to skip releasing Final Fantasy 2 in North America, instead opting to push Final Fantasy 4 on the upcoming SNES. Thinking the gap in releases would confuse silly Americans, they renamed it Final Fantasy 2 and buggered the whole chronology up, confusing silly Americans.
Anyway, while the original NES game never released in North America officially, a copy was made for a trade show, and that copy is now for sale on eBay for a whopping $50,000. According to the seller, it's the only one in existence. Surprisingly, it's playable from start to finish in English, though the translation is wonky at times.
The seller says he's had the game for nine years, and doesn't specify why he's selling it now (waited for it to peak in value, perhaps).
So far there are 34 offers on it, but none appear to be for thefull $50k. The cartridge can be shipped worldwide.