This novel got 6th place in "Kono Light Novel ga Sugoi! 2009", 8th in 2010 and 5th in 2011.
So it is famous enough to get an anime, I wonder why they make it sooner.
Here is some of the characters:
On the right are our MCs: Sato Yo and Yarizui Sen
And here is one of the fight scenes:
And remember, they are fighting for a half-price Ben-to!