I may be the last one to discover these (and I haven't read all the threads), but if you go to Amazon, and possibly elsewhere, and search for "Megapack", you will get hundreds of huge collections of pulp fiction (sci-fi, detective, western, fantasy - did someone mention Robert E. Howard?) and some good stuff (Poe, Hawthorne, Saki) for your e-book, and all for zero to $1.99 each. Ten bucks will get you across an ocean.
Apologies if someone else has mentioned this elsewhere.