One of my favorite people in the world (and partial originator of the 'janicu' nickname) came to New York City last week over Memorial Day Weekend. Besides our usual (the MoMA: all six floors, and then food), we visited Book-Off, which is at 49 W 45th St, just a a short walk from Grand Central.
This place is magical. Basically it is a used book store, but it's a Japanese chain so there are a lot of Japanese books and manga there. There used to be a Book-Off about 10 minutes away from me in Hartsdale, NY but that was a short-lived venture - probably because there were a lot more books in Japanese than English and I don't think very people really knew it was there. But this Book-Off, the one in NYC? It has plenty of English books. It has rows and rows of used DVDs and CDs in the front, a huge sale section in the back, magazines to one side, and then a floor below with Japanese books and manga, and an upstairs balcony with I think non-fiction (but don't quote me because I was just glued to the fiction shelves, salivating and petting bindings). Also many books are on sale for $1. MANY MANY books. The books that are not on sale: about $2.50 for a paperback and $5 for a hardcover. It's not too shabby. I also prefer it over the Strand when it comes to its selection of genre fiction: SF&F and Romance in particular. The Strand does have a bigger YA section and general fiction section, but I think Book-Off beats the Strand's prices because all the books at Book-Off are used.
You can open the drawers on the bottom of the shelves and there are more books!
Anyway, if you happen to be in New York City, I'm just saying this place exists.