What are the costs associated with a SaaS-linked Office add-in?

Thanks Kidd_Ip. It seems there's a lot of documentation about the technical aspects of creating an OfficeJs solution, but very little about setting up the infrastructure and processes around it. It would be very useful to have a "Step-by-Step guide to set up a subscription-based addin", starting from an individual developer with a personal MS login and ending up with a published subscription-based app, including the organisational and financial aspects, not just purely technical.