Any suggestions about Europe countries where studying Masters/MBA is free for international students?

Absolutely NOT! No truly "free" education for international students anywhere in or out of Europe. Even where university is "tuition-free" at bachelor's degree level, you need a great deal of money for remaining school + all of your living expenses + return transportation to your country of citizenship. Proof of sufficient funds required to apply for student visa (in addition to fluency in the language of the country).

Studying MBA abroad is often a very bad idea. You can only work in your country of citizenship, so you need to know your country's GAAP, tax laws & tax accounting, etc, if you are in accounting/finance; your country's employment laws & practices if you're in HR; etc. And you need local references, recommendations, network, etc. to have much hope of job when you graduate since MBA & other biz-related degrees are a glut on most markets these days.

Nowhere.

If you want to study abroad, you need to pay for it.

None.

UK