Half Price Books sells new and used books and videos at low prices. There are a few dozen stores spread across 13 states in the midwest and and the west coast, as well as a whole lot in Texas. They buy books, cds, dvds, and magazines for cash at each of their locations.
Selection: Good, but not great
The selection at Half Price is not great, but you may find something you like.
My main interest is the technology section. As in most bookstores, about 50% of the books are dedicated to Windows and Microsoft specific technologies like .NET and C# and so forth. Among the rest of the selection are a good number of slightly outdated titles from O'Reilly. Expect to find a copy of Running Linux, Programming with QT, Practical C++ Programming or some similar title from everyone's favorite animal books. Aside from that, there are a lot of books on Java and related technologies, HTML, Flash, and a lot of other technologies. You won't find the most expensive or popular titles, but there's a lot of good stuff available.
In literature, fiction, and science fiction, you might find something by your favorite author, but you won't find a wide selection. You're likely to find most of the Hitchhiker's Guide to the Galaxy series and a lot of Asimov, and maybe some of your other favorites. But you probably won't find that latest sci-fi hit or anything by an obscure author. Unfortunately, the only Nabokov they have had on hand is King, Queen, Knave (A translation), and an old binding of Ada. That said, if you're just looking for something to read, you'll have lots of choices.
The rest of the store follows. The arts section has a lot of popular artists, classic and modern, but probably won't have one particular book you're looking for, and might not have something obscure or unusual. The departments for science and math, foreign language, history and so forth are all interesting to browse, but not canonical. However, there are a lot of books on any given subject.
Music, movies, and software
In the music department, there are a lot of CD's, but few of them inspire interest. Most of the Hanson and Backstreet Boys gets quickly migrated to clearance, but the rest of the selection is only marginally more interesting. You'll find a lot of classic rock and rock/pop from the mid 90's and before, mainly because HPB gets their CD's by buying them from customers, and not through the other channels they use for books.
The selection of movies is also not very interesting; you might find something you like, but you might not. There is a section specifically for anime, and I have occaisionally found interesting material there (Texhnolyze, Blue Submarine No. 6, Evangelion) but you won't find the most popular or most recent titles.
There are some interesting titles in software, mostly games, but nothing that you've been looking for, for sure. The most interesting buys I've found in the software department were when the store ended up with a lot of copies of Descent 3 for Linux and Quake 3 Arena for Linux.
Atmosphere: Doesn't feel like home
Half Price Books lacks the coffee shop atmosphere of large booksellers like Barnes And Noble. There are chairs here and there, but most outlets are very compact without a lot of open space, and there certainly isn't a coffee shop, though there is usually free coffee near the front throughout the morning and afternoon. The store is not decorous, but it is well kept and well staffed. In short, Half Price Books is a place more for buying books than for reading them.
Update: QuantumBeep informs me that the store in Dallas, Texas has an actual coffee shop, as well as reading areas with couches and chairs and beanbag chairs and suchlike. I'm visibly upset right now at how I've been abused and cheated by the stores here in Indiana. Oh well!
Pricing: The whole point
Pricing at HPB is very competitive. Most books you find there are new or in incredibly good shape. Most books are sold at 50% of the cover price, or lower if they are worn or outdated. Technology books are the only exception; some of the popular O'Reilly books may say $34.95 on the cover and cost $20, which more than literally "half price". Still, the titles they have are steals compared to shopping at B&N or Borders, and usually less than you would pay for a similar title on Ebay or Half.com.
Pricing of paperbacks in literature and science fiction are 50% of cover price, or less if marked. CD's are marked, and usually $8 or less. All other items are marked.
Selling to Half Price Books: Don't
Half Price Books will give you next to nothing for your books. You will have best luck with brand new books on popular subjects, but you will be lucky to get more than $5 for anything. In short, let them find their own books.
You may like it, you may not
Half Price Books certainly isn't for everyone. I like some of the titles they have, and half of my science fiction collection is from HPB; I've bought some anime, and a lot of books about Linux and programming. You may go there and find something you like, or you may go there and not find anything at all. It's worth trying though; after all, everything is half price.
My favorite purchases: