Sega programmed a small number of cartridges to display an 800 number when the player finishes the game. The first person to call that number received $25k. Here's an article about a kid who won

https://www.thefreelibrary.com/12-ye......-a017793447

Apparently it requires you to finish the game without cheat codes so itd take a while to figure out which carts contain the code, unless theres a visual difference on the PCB of a known Play to Win cart versus a regular one.

Might be worth it to play through your copy of Vectorman if you have it, could be one of the rarest known legitimate variants (opposed to error copies, upside down labels, discs containing the wrong game, etc.)