Books are piled and scattered on the floor - and aisles are narrow enough to let one person pass through, craning their neck to view anything on the top or bottom shelves. It is not a place you go if you get overwhelmed easily. But it's a treasure trove for anyone looking for inexpensive reading copies.
As with most used bookstores, I'm not quite sure how they determine their prices (I suspect Amazon.com plays a role). I found a signed, limited slip-cased edition of Danielle Steel's Daddy (#27/250) priced at $2.99. The only issue I could find with it was a remainder mark on the bottom - and while blemished, it wasn't enough to explain the steep discount. (later I would find this same title being sold on Abebooks for $125 by, none other than, Wonder Book of Maryland).
I found a number of signed, first editions - most of which were priced at $30 - $40. I can't tell you for sure why I passed up these books. Partly because I'd just paid my taxes and was feeling broke; partly because the manner in which the books were crammed in to the shelves left me a bit leery about their condition; and partly because I hadn't done my homework. Was a signed, first edition of Anne Rice's Violin worth $40? Answer: Yes... and no. If the copy was pristine - it might (MIGHT) be worth $80, but you can find signed firsts for this title for as low as $13.
I did find a very nice first (US) edition of Hilary Mantel's Wolf Hall (sans the Booker Prize sticker). Something I've been looking for since it was up for (& subsequently won) the Booker in 2009. I paid around $10 for it and it's worth between $65 and $150.
I can tell you this, the next time I go (and I will go again), I will do my homework because there's nothing more exciting than finding a treasure socked away among thousands of books. I imagine it's the same high that extreme couponers feel when they've just saved a ba-jillion dollars on ramen noodles and glade scented candles.