The Leanpub workflow is totally free to use, and we're making it better all the time.
Now, frankly, I'm a programming book author myself (I've written 3 programming books) and we have tons of programming books on Leanpub -- but I really wish we had a lot more romance and other "genre" books than we currently do. I even went to Brisbane to speak at GenreCon Australia (http://www.genrecon.com.au/) in 2013 to try to jump-start this, but frankly our usability wasn't there yet. We'll get there.
It's been a really pleasant experience so far, although my chosen topic feels a bit broad, as it encompasses everything from running a website to marketing, shipping, packaging, curation, customer service etc. and it feels difficult to really get too deep into any subject. And the reality is that running such a box by yourself is exactly about being a generalist in all of this stuff.
At this point I have about 60 pages written and am now commissioning a book cover on 99designs: https://en.99designs.jp/book-cover-design/contests/create-e-...
I'm plotting a way to A/B test these covers. Maybe do an ad campaign with 1/6 of traffic getting each cover and see how many email signups each one gets. My leanpub page is looking rather bare now without one: https://leanpub.com/subscription-box
Any plan for improving the search engine?
Maybe a subtitle would help? "Hello Web App: Making Your Own Django App" or something.
Fantasy has one entry, scifi has no entries and fiction has a total of three entries.
To support fiction properly, we need to add support for paying for instalments, so that you can buy a chapter at a time, etc. Serial fiction used to be a big deal in the 1860s, and it should be a bigger deal now because of the internet.
Also, we're working on a new version of our in-browser editor which will be more friendly for people who don't like writing in Markdown -- which probably includes many fiction authors...
Thanks for the suggestion regarding pre-orders. At some point we'll probably add this. It would have to coincide with our also adding store credit, so that we can give refunds to purchases that are older than 45 days in store credit, etc. (Right now we have a 100% "happiness guarantee" where readers can get a refund with 2 clicks, but this only works for 60 days, so we set our refund policy to be 45 days.)