Amazon offers Prime members Tony Mitton's Amazing Machines: Truckload of Fun 10-Book Set for $11.60 with free shipping. (Non-members can spend $35 or more to qualify for free shipping; otherwise, shipping costs $4.98.) That's the lowest total price we could find by $3, outside the mention below. This set includes ten educational books with illustrated glossaries of technical words to help build vocabulary.

Orders placed by December 22 are guaranteed to arrive in time for Christmas via Prime shipping; otherwise, choose Standard shipping and place your order by December 19 for guaranteed delivery.

A close price, Walmart offers it for $12.66 with in-store pickup.