With orders of $25 or more, Amazon offers Prime members the Fisher-Price Brilliant Basics Activity Puzzle, model no. W9839, for $5 with free shipping. (Non-members can spend $35 to qualify for free shipping.) That's the lowest total price we could find by $13. Designed for children between 12 to 36 months, it features activities that teach matching and problem-solving skills.

Note that this item is part of Amazon's add-on program and can only be purchased with an order of $25 or more.