These all are places I've visited in the past 6 years, and the emphasis is on stores primarily in the Eastern USA, if only because I live in Central Virginia........
Needless to say, every one of these places is going to have a surfeit of paperbacks by Piers Anthony, Marion Zimmer Bradley, John Brunner, Andre Norton, etc. But they also have, for the careful searcher, some less prevalent titles.
With each store, I sum up the good and bad.
I also note whether or not if the store buys used books. Needless to say, you probably will not get the return you are expecting if you elect to sell your books for cash, and you usually are better off opting for 'Store Credit' for these exchanges.
McKays Books, Manassas, Virginia
8345 Sudley Rd., Manassas, VA 20109
McKay's Books is located in the Manaport Plaza Shopping Center, a nondescript shopping center in the 'Little San Salvador' section of Manassass.
[Take care where and how you park - 90% of the other drivers in this part of Manassas not only don't speak fluent English, but they also don't have Car Insurance......]
The good: a very large selection, among the largest of all the stores reviewed here, including a healthy selection of older paperbacks. There also are separate aisles for fantasy and horror, with large selections as well. Paperback books are usually in the $3 - $5 range.
There is a large selection of graphic novels and art books, but these are priced rather high.
McKays will buy books from you.
The bad: the books have a large, very very sticky price sticker on their front cover. If you succeed in peeling it off, the residue left on the cover of the book will adhere to anything it comes into contact with - if you lay another book atop it, there will be consequences......
Wonder Book and Video, Frederick, Maryland
1306 West Patrick St., Frederick, MD 21703
Wonder Book and Video is a three-store chain in Maryland; there are stores in Hagerstown, Frederick, and Gaithersburg. The latter is tucked away in the obscure back parking area of a shopping plaza, and is hard to find - I recommend that if you go, you print out a map beforehand, and be careful about over-relying on your GPS.
There is an entire section of the store set aside to vintage nudie and softcore books, magazines, and memorabilia.
Uncle Hugo's Science Fiction Bookstore
2864 Chicago Ave S, Minneapolis, MN 55407
Uncle Hugo's shares a building with Uncle Edgar's, a mystery bookstore. Chicago Ave S. is a main drag in Minneapolis, so you may have to find parking a block or two away from the store.
Uncle Hugo's also has a large section for new sf books, including hardbacks and small press.
10201 University Ave, Clive, IA 50325
When I lived in Iowa, I routinely drove from my home in Ames to this Half Price Books location in the Westridge Shopping Center in Clive, a suburb of Des Moines. I also went to the Half Price store in Marion / Cedar Rapids.
The sf paperback sections in the Half Price stores I went to in Clive and Cedar Rapids were small compared to those of the other stores I review here, and were primarily comprised of newer titles. Nonetheless, with a bit of searching, you may find some books from the 70s and 80s. Book prices were in the $2 - $4 range.
So there you have it. Good luck with your scores.......!