I live in Budapest, Hungary, and we have DM (Rossmann too) over here too. It stands for Drogerie Markt by the way, and they do not have an online shop, but you can find them at pretty much every mall, etc. The Alverde & Balea stuff is pretty great, yes. Those are DM's own brands. It's all organic, as far as I know. As for styling products and such, I personally haven't had ANY luck yet ( I order my LA Looks Gels from amazon.co.uk marketplace), and I've tried basically every gel they have over here. IDK. But I agree with GermanCurls, the expensive stuff is always full of cones, and usually the cheap ones are free of them!
If you have any questions, feel free to ask, as I know for a fact Hungary gets pretty much the same beauty/hair products as Germany, Austria, etc.
Sometimes I wish I lived in the UK though, they have Boots and Superdrug and other great stores, and it's much easier to get hold of REAL good, curly-friendly organic products there.
Have a great trip!