Original LEGO Medieval Castle Set ($3,300)
LEGOs have always been popular since the company was created in 1949. Since then they have created several thousand sets over the years that have become extremely sought after by collectors. One set that has become highly collectible is the 1978 Medieval Castle set which features several figures and a huge yellow castle that you build.
This set was relatively inexpensive when it was first released but now it is worth around $3,300 new in the box. If you have the complete set, but it is used, you can still get around $400 for the set. There are several LEGO sets that have increased in value over the years and are worth several thousand dollars.