I know Delphi Classics are pretty popular with some folks here. Was just on the site and saw they're offering a buy one get one free sale this weekend. I added a couple of books to my cart and the second one was automatically marked down so no coupon code or anything is needed.
On another note I notice a bunch of their titles are marked down to
$0.99 on Amazon including Complete Works for Wells, Dickens, Verne, Conan Doyle, Kipling, Twain and more.