Is it only me?

Is it only me that cannot walk away from a box of stuff labeled "free"? I went to check out our new TMH/PMH classroom today and she happened to be giving away some of her old teacher books. Now, keep in mind that I am a book junkie and have file cabinets and shelves full of teacher books, but I could not just make myself walk by the box without looking in it. It was like Christmas! I even got a copy of Reading with Meaning (which I've been wanting to read for a while). What is it about the word "free" which translates in my brain to "you must have it"? This is why you can't walk into the closet in my classroom. Oh well, if I use it at least once, "free" was worth it!