This is quite the story...

According to Redditor L064N, he was shopping at a thrift store in Oceanside, California last week when he came across a very strange Atari console. Some quick Googling told him it was a rare prototype for the Atari 2700, an un-produced wireless follow-up to the 2600. He bought it for $30.

And then he sold it on eBay for $3,000.

Planned for release in 1981, the Atari 2700 was a new iteration of the popular early video game console. Compatible with all Atari 2600 games and accessories, the core difference between the 2700 and its predecessor was a pair of wireless controllers that combined a joystick with a paddle.

Read the full story here:  Kotaku