Barbara Coyle, donations director for Better World Books, said the company does a "beautiful thing" that's a "win win" for everyone by donating a book for every book bought on the website.
Better World Books is a global online book store that promotes literacy around the world.
All the books were donated free of charge and have a value between $1 and $30.
"Experiencing the end of what she starts" is how Coyle explains her favorite part of visiting after creating a friendship with people who need donations.
"I get the calls or emails and send the books. To come and experience that end result is the best," she said in reference to being able to see the children receive their book and visiting with Santa on Wednesday, Dec. 18 at the castle.
A book with a signed autograph from Santa Claus has become a big hit at the castle according to Ron Hott, the board president.
"Each child gets a book that is worth more than their fee to get into the castle and then they get to experience the castle. Kids have even come back to show us books they had gotten from the castle from previous years," Hott explained. "These books have really taken Santa's Castle to the next level."
Kids also have the option to write Santa a personalized letter that always gets a response. Even Coyle says Santa's Castle makes her "feel like a kid again."
Approximately 2,000 books have been handed out to children in this year's Christmas season alone. Hott estimated that 3,000 to 4,000 will be given away in total this year.
It all began four years ago.
In 2009 the Storm Lake Public Library sponsored a night at Santa's Castle and donated 26 books. At this time the castle didn't hand out a book to every child. The books were such a big hit that Hott began researching ways to get more books.
He stumbled across Better World Books. Willing to help in any way possible, they sent 1,200 books in 2011, and because they were so popular, sent 3,000 in 2012. Both years the castle ran out of books.
During the 2012 incident, when the castle ran out of books, they contacted Better World Books again during the season to let them know they ran out and were in need. Better World Books decided to send an additional amount of 400.
With the 5,000 books received this year, plus an additional 300, the castle will keep whatever is left for next year's inventory.
Coyle said, "We made sure they got well over 5,000 this year so they wouldn't run out."
She added, "We try to send books with the Christmas theme. If not, we have plenty of other books to send."
Better World Books receives the books and then stores them in its warehouse before sending them to organizations and people, filling requests from various non-profits around the world. According to Coyle, they house 8 million books and process three quarters of a million books a week.
She said, "Instead of causing them to end up in a landfill or shredded, we look for organizations to partner with."