Are there any costs at all for these free certification courses?
This would also depend on the course as well as the course provider. For example, Udemy offers specific free certification courses that are completely free. Other times, they offer very inexpensive courses, which you should also check out. When it comes to Alison, all the courses are free. There are also providers such as Swayam (Govt. Initiative) which offers free online courses with certificates in India.