Walmart offers the K'NEX Super Cyclone Motorized Coaster Building Set, model no. 50063, for $19.97. Opt for free Site-to-Store pickup to avoid the $2.97 shipping fee. That's tied with our mention from two weeks ago and $17 under the lowest shipped price we could find. Sales tax is added where applicable. It includes 675 pieces and requires two AA batteries (not included.)