I'll tell you about value!

I just got back from attempting to sell my textbooks back to the SMU bookstore and was shot down repeatedly with the following phrase, "Sorry - these books no longer have any value.  We just got new editions."  That is simply the most ridiculous thing I have ever heard.  Not only was I upset that I wasn't getting money back for some pretty expensive books (luckily, I'm not a chump and I bought my books off of Amazon), but what the salesperson said really got to me.  No value?  I've always been taught by my family that knowledge is the most valuable thing you can ever have; An education is the one thing no one can take away from you.  And yet, here, this young lady looked at me (while quite obnoxiously smacking her gum at me) and told me my books had no value.  I know, I know - it's not her fault.  She only told me what the computer dictated to her, but I will tell you one thing, I will not sell my books to anyone/anywhere that does not find value in them.