Walmart offers the LEGO Technic Class Xerion 5000 Trac VC Tractor for $115.13. Choose in-store pickup to drop it to $112.25. (Amazon charges the same with free shipping.) That's the lowest price we could find by $7, although we saw it for $7 less in December. This 1,977-piece kit includes a LEGO Power Functions motor and can be configured to carry out a number of motorized functions.