GITAM School of Business, Visakhapatnam

Hi,
Firstly, German language course fees depend upon the institute & the platform from which you are taking it. If you want to take it online then the fees structure will be different. I prefer you coursera for the e learning. Now, if you want to take it offline then it depends upon your location also. The level of language also play an important role in it. If you want to learn b1, b2. C2 level German language, then definitely fees will high.

German would be an easy language to learn for people using English as a medium of communication. The difficulty level of German language is less than Korean.

Mumbai University does offer a few foreign language courses. But, institutes would depend on the language you wish to learn. They are really spread out.

No, it's not compulsory. No such requirements are mentioned.

You can use this tool to compare both these colleges.
https://www.shiksha.com/resources/college-comparison.

DU offers a wide variety of foreign languages like French, German and Korean in three levels. For certificate course, eligibility is your (any) previous examination marks. Eg. class 12th marks, UG marks or PG marks.
Diploma course's eligibility is your score in certificate course examination. Final level is Advanced Diploma/Advanced Certificate where your eligibility criterion shifts to the previous examination taken for the language.

If your college allows that then certainly you can.