That's right, I saw a SEGA Mega Drive Master System Converter. For the ill-informed and millennially-impaired, I will briefly explain that SEGA once made hardware that played games. Their first foray into the home market was the SEGA Master System, which while superior in everyway to the Nintendo Entertainment System, was a commercial failure. As a concession to their stillborn system, they made an adapter that allowed their next hardware, the Genesis (or Mega Drive as it was known outside of North America), to play games from the now-dead Master System.
This relic was not particularly valuable in the game collecting world, as Master Systems could easily be picked up for $12-$20 for many years, and so I never bought one, since it was easier to actually accumulate four fully functional Master Systems without even particularly trying.
Enter the Retron 5. Now that this incredible contraption makes playing old games easy on HDMI televisions, the converter has become greatly valued, usually anywhere from $120 to $250 on Ebay.
So in this store, I see one. For $60. I wave over the owner. He says, "Ah yes, you don't see many of them, I've sold and re-bought that unit twice."
I said something like, "Okay, yep, I'll take it." I paused to ask, "Um, all my games are NTSC (US) carts, will this work?" He motioned to put the adapter back in the glass case and said, "NO!. This won't work with NTSC, won't work, needs to be Australian games..." and then in a moment of apologetic anti-patriotism added, "...PAL, PAL games, will only work with PAL games sold in Australia".
I looked at it again, with the $60 price tag, and now with my significant other walking into the store, said, "I'll take it, it will work with the Retron 5." Not wanting to admit his ignorance he paused momentarily and said, "Uh, yeah, okay, well, it won't work with American games".
So cutting short my vacation I took it home, plugged it into the Retron 5 with a copy of Outrun and found that it did indeed work. It worked with that, R-Type, Alex Kidd and everything else. And while that is likely the last time I will use it, I felt like I had won.