One thing not mentioned in this post is the minimum amount you need to have in the bank. I've heard people with as little as 3k, but technically Germany asks that you have 10k in the bank to prove that you are economically viable even between jobs. It's up to the discretion of the person at the Foreigner's Authority who decides on your application.

It is much easier to obtain the freelancer visa after you've worked for a german company for some time. I know people who have been rejected from the freelancer visa for not having sufficient money in the bank.

You can also just ask friends/family to loan you the money so you can take a screenshot of it to show to the person at the foreigners authority ;)

Edit: Also, if you're really interested in moving to Berlin/Germany, I have a bunch of content about this on my blog (incl. the entire process end-to-end) you might find useful: http://notanomadblog.com/categories/work-abroad/