Am I getting a good deal on 2015 DAT Destroyer?

Hi this is my first post, so forgive me if format is wrong. Someone is selling their 2015 DAT Destroyer & Math Destroyer for $50. I'm not sure if that is a good deal or if I am getting screwed over. I also didn't know who to ask. lol. Thanks in advance for the advice!
Source: Student Doctor Network - Category: Universities & Medical Training Authors: Source Type: forums