Walmart has theÂ K’NEX Imagine – 25th Anniversary Ultimate Builderâs Case on sale for only $35.56! (Reg. $53.99) Plus, you’ll score FREE shipping on this item too. This set contains 750 classic K’NEX pieces to build 52 different models. These models include a pirate ship, robot, car and more! This is a great way to get your kids imagination working. Great holiday gift idea!