I've been looking around a lot for info, but I can't find much related to my exact topic. What do I need to get a residence permit if I'm an American in Germany who doesn't want to work in Germany?

I saved up a lot of money before I came here (especially considering how cheap Berlin is) and I am self-employed with my company based out of the United States. I simply want to live in Germany for the culture-- is that hard to explain to an office without sounding suspicious?

So, I guess I'm just basically asking what I need to show them to get a residence permit here? I'm guessing something like:

* passport
* photos
* address registration

and then the following i'm unsure of:

* proof of insurance?
* proof of income or savings?

Any help on this topic would be very much appreciated. I've only been here for a few weeks, so I have plenty of time left on my initial visitor visa, but I've been told by multiple people that it's best to get on this ASAP.

Hello, my name is sabine and I am a lawyer. Maybe you are eligible for a residence permit §7 AufenthG. If you want to make use of an initial consultation contact reeder@trust7.com

Regards
Sabine