SimCity Code Has Already Been Used

I bought SimCity 2013 from Deseret Industries, a thrift store here in Utah, for seven dollars. And my idiotic self thought I can play it. So when I got home and put the game in my computer, it asked me for the code in the container, I inputted the code, and it told me it has already been used. I thought I may have made a mistake so I tried it again, and again I got the message. So now I have wasted seven dollars unless I can find a way around this issue.