The cost of a digital marketing course starts from 100$ onwards upto 300$ depending on the type of course content, skills and mentorship offered. This cost applies to a short-duration course. At times, this cost could be less if it is self-paced learning.
If you choose a degree-granting educational program from a geo-specific university or institution, the fee will go up.
Here's related information that you may find helpful - Beginner’s Digital Marketing - 33 Most Frequently Asked Questions (FAQs) And Their Answers To Start Confidently.