Two answers:

• The operating costs are very low, since all Easyful does is email your customers your content when they buy it.

• Our team at nicer.io is primarily a product agency, so when we make our own apps like Easyful, SimplePerks and Smallchat, they don't have the pressure to be highly-profitable. We often end up getting good connections, agency customers and referrals from these apps, and keeping them running and supported is pretty low-cost for us.