Seriously, less than $5 and ten minutes time and it was done. The plans give you a choice of two different lengths, one for the 24 inch shelf and one for the 36 inch shelf (we went with the 36 inch one). When Audrey came home from school she was thrilled with her new shelf and began to fill it with some of her books. As you can see she's already putting it to good use.
I think it's safe to say we got our moneys worth.