If you wanna try to use reddit I recommend giving a free ebook/sample/snippet or whatever inside of a post, then at the bottom of the post you can say 'taken from my ebook' and link to a landing page/website with the freebie you promised in the post with ads and CTAs to buy the full thing pushed somewhere in there. If its quality material reddit community will let it slide and you might get a huge promotion, but if it's subpar content or too salesy reddit will smite you down so hard you won't recover. So no salesy tricks at all, just a simple 'this was taken from my ebook, you can check it out (or 'you can buy it') HERE.
Never try to push yourself too hard with reddit community, you can only offer something with absolutely no expectations to get anything in return, and if they judge you worthy it's payday.
source: a frequent Reddit user.