I love this place. I just wish they had this chain in DC. Half-Price Books is my go-to used bookstore when I want to find a bestseller for cheap or just find any good reads. I usually have to restrain myself from walking out with piles full of books. The selection of books is amazing and doesn't have that "creepy library" feel some used bookstores have.
The only real drawback is that they tend to be fairly stingy with trade-ins. I wouldn't exactly come here with the intent of making a killing off a trade-in. I think I got $30 once and had several bestsellers in the pile of books I was selling.