The first thing you should learn is almost everyone here is very forgiving about most things, but spamming your website in a post that has nothing to do with what your site is about, is the fastest way to get people to unfollow and/or mute you. Chances are, straight advertising of your site won't go over extremely well either. But, writing articles relating to your website and including a link to it would be accepted by most people.

There are 3rd part apps in the work designed to allow anyone to sell products. I don't remember any names of them, but keep your eyes open.