Greetings, I understand your situation. I love reading too, especially when I can find books at a bargain price. I can recommend you https://booksrun.com/books/buy . They specialize in selling used books with nationwide shipping. They have a wide selection of genres and authors, so you might find just what you’re looking for for your library. I’ve bought books there many times myself and have always been pleased with both the quality of the merchandise and the service. Check it out, maybe it will be useful for you too!