1.There is no special meaning just emphasis. 2.I'm interested in customs of Yunnan minority nationalities 3.In this sentence, because the punctuation is the exclamation point , so it means "spend a lot of money", if it is a question mark it means "how much".

For question 1, sorry that I’ve no idea what the whole sentence means, so I can’t answer it. Question 2: I’m very interested in the custom of Yunnan ethnic minorities. Question 3: “多少” means “how many” or “how much”. In this sentence, as “多少” is followed by “钱”, which is uncountable, so it means “how much” here. Hope that you’ll find my answer useful.