Given all the work required to maintain a POS on your own website, even a "no coding" one, is way more work than most people want to bother with. I'm a web developer myself, and the moment you put a POS on your site, you paint a gigantic bullseye on your chest. That's why I leave it to the big boys like Smashwords. All I have to do is put a link on my site to the sales page on theirs, advertise, then sit back and enjoy the sales. Really, there's no need anymore to sell directly off your website.
I'm not trying to crush your dreams or anything, but practicality says that the blood, sweat and tears required for an author to keep up even a "no coding" system is going to cost a lot more than the 15% they'll get from selling directly off their site. Personally, the best approach would be to come up with some way to help authors defeat the dreaded plague of obscurity. That alone is worth the 15% cost of hosting at Smashwords or up to 50% at some other retailers. (cost here refers to the percentage retailers take out of the sale price of your book)
So my best suggestion for you would be to focus on curing the obscurity plague suffered by most authors, as it'll be a much better and more profitable way to invest your time and energy. You're welcome to take this with a grain of salt if you like, but as an author and a web/cloud developer with quite a bit of experience, I do have a bit of experience at this.
