LEGO 400 Building Set is a vintage Universal Building Set set from 1977 valued at $537 for new and sealed sets, up 2047% from an original retail price of $24.99. Annual appreciation has averaged 6.50% since release. Used copies are valued between $26 and $36 depending on condition.
LEGO 400-1 Building Set is a Universal Building Set/Basic Set released in 1977, containing 294 pieces and 3 minifigures. Sold only in the United States, it was also titled Universal Building Set and is equivalent to set 910 Advanced Basic Set released in Europe, the UK, Canada, and Australia. The assortment includes classic and modified bricks, slopes, plates, windows and doors, and functional elements such as wheels, a red string reel winch with a metal handle, a yellow collapsible ladder, and a black forklift with a yellow fork, plus a green baseplate with rounded corners. It features three early LEGOLAND minifigures, two in black outfits with black hats and one in blue with a matching hat.
A new and sealed Building Set is currently valued at around $537, with annual growth of approximately 6%. The average used price is $30 for those in good overall condition. Based on current trends, this set could be valued near $569 within the next year. The 3 included minifigs account for approximately 10% of the set's total value.