Run a writing competition, and attract as many entries as you can: the internet makes it easy to find writers’ groups and message boards where you can advertise your competitions for free. You don’t even have to charge an entry fee: just get as many entries in, as quickly as you can.
You don’t need to read the entries as they arrive. So what if some of the submissions are stories for children, and others are racist rantings or violent pornography? It’s quantity you want here, not quality: just bundle them all together into a single anthology, stick an ISBN onto the cover, download it to a POD service, and that’s all your editing and production work done.
The marketing is very easy: all you have to do is tell all the entrants that they’ve won a place in the competition, and that their work will appear in your prize-winners’ anthology. If you want to you can get your anthology stocked on Amazon, and other online retailers; but there’s no need. You can sell it from your own website, and that way you don’t even lose the discounts that those professional book sellers demand: you get to keep every penny that the book earns.
Price the anthology high, and wait for the orders to come in. Chances are that most of the people who are included in it will buy at least one copy; probably more. They’ll make excellent gifts for their family and friends who will probably be too embarrassed to say anything about the dreadful writing the anthology contains; and it’s not your problem that when writers claim your anthology as a professional publishing credit they’ll lose any credibility they had. You didn’t promise them anything more than they got.
It’s a failsafe way to make money out of writers. It’s just not a very nice one.