Okay well I am not going to jump on the bandwagon of people gleefully slinging arrows at this woman. Would I do what she did? No, can't say that I would. If I did, I certainly would not tell anyone about it (wonder why judging from all the comments here). That being said, I do not personally require that a gift be brand-new or top dollar quality. If someone had something laying around their house they knew I'd like and gave it to me, I'd be just as happy as if they went out and bought me something. If someone gives me dollar store junk I have no use for, I toss it in a box for a future yard sale. If someone else likes it, I pass it on. Simple.
I do understand why people think her actions were tacky and I would be inclined to agree that her talking about it at the exchange was not her smartest move. That being said, does the fact that she has read the book she gave you inhibit your enjoyment of it? Probably not. So read the book and be happy, as you plan to.