Simple. Just browse to…

 

missionbooks.org/collections/paperbacks

 

Fill your cart with at least $25 of paperbacks then add Operation World…

 

missionbooks.org/collections/perfect-gifts/products/operation-world-2010-7th-edition

 

and… bam… when you check out, magical elves will subtract the price of Operation World. You’ll pick up the book for free! Just order by December 13th to make sure your books arrive by Christmas.