I have a weakness for the library book sale dollar bag days. And Half Price Books is like a crack house. But if pulpy SF is your passion, you have to seek out the dingiest, out-of-the-way paperback exchange you can find. You will not be disappointed by the treasures found therein.
I’m a total sucker at library book sales, when it’s 50 cent paperback time I’ll grab anything, if I think there’s even the slightest possibility of me actually wanting to read the book at some point before I die it’s in the bag. Because heck it’s 50 cents, two books for the price of a vending machine soda hard to feel like you’re wasting money. Thrift shops are great too, never really know what you’ll find but it’ll be dirt cheap, along with dirt cheap music. I often find it hard to excuse buying entertainment products new.