Catan 5th Edition | $30 | Amazon | Clip the $5.30 coupon
I would posit that Catan is basically the Monopoly for the modern board game landscape. Pretty much everyone knows how to play, everyone owns a copy, and it’s a good default activity for a small group of people. There are better German-style board games (in the same way that Life or Clue is better than Monopoly), but at least Catan is a lot better than Monopoly.
There have been a few deals on various styles of Catan lately, but $30 is a really good price for the standard edition. Bug customer support enough, and they might even sell it to you for two bricks and a wheat.