A master’s degree usually has a higher upfront cost, but it also allows you to start earning a higher salary more quickly. The exact cost depends on the country and the school: private universities usually cost more than public ones, and European degrees usually cost less than North American ones. There are limited possibilities for financial aid.
PhDs often waive tuition fees and offer a living stipend in exchange for a teaching or research assistantship. However, they take many years to complete, during which time you earn very little.