Walmart offers the LEGO Scooby-Doo The Mystery Machine Set, model no. 75902, for $20.99. (Amazon charges the same price, for Prime members only, with free shipping.) Opt for in-store pickup to avoid the $4.97 shipping fee. That's $4 under our mention from two weeks ago, the current best by $4, and the lowest price we've seen. This 301-piece set includes three mini-figures.