The Oatmeal - 5 very good reasons to punch a dolphin in the mouth:  $4.99 @ Value Village (RSP:  $16.99)

I normally don't buy used books, but when I saw this one on display, I just had to take a look.  Just read the title!  I had to know what was inside.

Well, turns out it's a volume of hilarious comics.  Seriously!  I haven't laughed that hard in a long time.  I spent a good amount of time just standing there and reading it, but I wouldn't have bought it just for that.

This is why:

It's signed by the author, there's even a drawing on the inside cover!  I thought that was special.  Otherwise, I probably would have just read it online or bought a new copy somewhere else.