This Lego brick, the most expensive in the world, has sold at auction â for a whopping £8000. See SWNS story SWLEGO: One of only a handful of 14k solid gold 2×4 bricks ever made sparked a bidding frenzy when it was put up for sale on auction website eBay. Between 1979 and 1981, the extra special bricks were originally given to Lego employees that had fulfilled 25 years of employment at their main factory in Germany. What makes this commemorative brick even more special is that it can be used with all other Lego sets, thanks to its patented interlocking nodules.