OBI / Bauhaus / Aldi sometimes have sales for full kits

Obi has this one at the moment for example: https://www.obi.de/p/2191115656515/solakon-balkonkraftwerk-900w-800w-solaranlage-steckerfertig-komplettset-photovoltaik-anlage-800w-kabellaenge-5m

I have to add that i know the Growatt inverter(Wechselrichter) that ships with this kit and the monitoring it has really sucks. It does its job of generating electricity just fine however, so if you dont need monitoring or can build your own then it doesnt matter.

The built in monitoring with most inverters (expensive or not) is proprietary garbage that only works with the manufacturers app which is often some weird chinese app that wants location permissions. You have been warned :D

But yeah they are becoming insanely cheap. Last i checked you do not need to register a balkonkraftwerk with your electricity company or landlord up to 800W so that makes things very simple.

Edit: The app in question.