Financial terms and conditions depend on the way of Stepik-Instructor cooperation, as well as on the provided services. You do not have to pay for a subscription (unless you want to have both free and paying learners at your course) but part of the course cost goes to Stepik.
12% of the sales goes to Stepik, remaining 88% is paid to the instructor. Stepik can also help with promotion of the course: If the payment is made from the catalog or search, 30% of the sales goes to Stepik, another 70% is paid to the instructor.
If your course is in US dollars, Stepik transfers your share to your Paddle account after each payment, and you can choose when and how you will transfer them to your personal account.
You can see all the Stepik course sales statistics in Payments report in each of your paid courses.
Stepik does not assume any tax obligations for paid courses. After you transferred the money from Paddle, you must pay your taxes yourself on the basis of your taxpayer status and laws of the country of your residence.