While you have free tools like Mautic, let's not forget the expense of hosting it and maintaining it. Moreover Mautic works for experienced people, and it is complex too. The question here is specifically for early stage startups, hence recommending expensive or complex products may not result in offering a guided assistance. Try Retainly, built with enterprise grade, but priced to be most affordable in the world, what else will an early stage startup need? Beautiful application, with some very different and unique features too. Startups are enjoying it.