Amazon offers Prime members Jean Marzollo's Help Me Learn Addition in hardback for 64 cents with free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $5.62.) That's the lowest total price we could find by $12. This 32-page book is aligned with Common Core State Standards and is geared toward pre-schoolers, kindergarteners, and first graders.

Of note, this item is temporarily out of stock but can still be purchased at this price. No estimated ship date is given.