Some of the more rarer Nintendo DS games can be worth some decent money. In fact, there's quite a lot of old consoles and games that are very sought after, including the vintage Atari Lynx and Sega Game Gear hand held consoles, rare N64, PS1 and Sega Megadrive games. And lot's of others. I thought this could potentially be one that might be worth something decent.
But doing a quick bit of research online, or more specifically, checking out some eBay listings, its clear to see that Scooby Doo First Frights for the Nintendo DS is widely available for sale and selling for between £5 and £10 depending on condition, and whether it comes boxed with instructions / guide or not. Ah well, better luck next time. Still a cool little find though. I wonder if it actually works. I don't own a DS, never have, so I'll probably never find out.