cross-posted from: https://feddit.org/post/19852594
Edit: Be aware that some people try to post misinformation here, such as that such plants are not safe in the case of a power failure (untrue), or that they are not economical (untrue, their advantage is that they have very low installation costs).
In Germany you can get an 800W system, so two solar panels, a converter and cables for 250€. You usually need some sort of attachment as well, which is another 50€ or so. They are surprisingly cheap.