Walmart offers the K'NEX 375-Piece Deluxe Value Tub, model no. 13597, for $11. Opt for in-store pickup to dodge the $4.97 shipping fee. That's the lowest price we could find by $8, although we saw it for a buck less last December. This set includes 375 pieces and ideas to build 30 models, including a truck, helicopter, and dune buggy.