There are links in stories. But it’s not for everyone (you need to have 10k+ subscribers). Links on posts are not clickable so they’re inefficient. Most people won’t even bother putting a link in a post.
I’ve been testing lots of possibilities on different audiences and all I can say is that Instagram is pretty bad to drive sales or traffic if you compare it to Facebook, Twitter or LinkedIn. I’m not saying that it’s impossible to do such things or to have outstanding results using Instagram. I’m just saying that the way Instagram works is not making it an easy process to achieve those goals. And I think that those efforts should be put towards other channels that makes it easier for you to get traffic or to drive sales.