I'm back, with mixed feeling about the trip. I used Mitfahrgelegenheit.de to get from Düsseldorf to Hamburg as cheap as possible. The train fare is between 39€ (if you're lucky enough to get one of those tickets) to 71€, so I chose a service where people travelling into the same direction by car can find companions for the trip and share the costs for gas. In contrast to Mitfahrzentrale.de, Mitfahrgelegenheit.de is free and you get the phonenumber directly, the other service lets you exchange emails or call an expensive service number to get the phone number. I planned to stay for a maximum of three days, but the place I planned to stay at turned out to be a bad idea. The Hospitality Club is a free hospitality exchange organization in lots of countries world wide. There are over 54,000 members in 170 countries, over 11,000 in Germany alone. Usually people participate to meet new people from other countries or they travel a lot as well and don't want to stay in a hotel. Accomodation is free, sometimes you're asked to pay for the phone (if used) or food. I had to copy a few books and magazines at the Institute for Asien Studies, so I looked in HC's directory who lived in the neighborhood. There were half a dozen people in five minutes walking range, so I mailed them and one wrote back. Unfortunately, that person turned out to be an extremely difficult person when I arrived. Instead of an apartment-sharing community, I was welcomed by a completely drunk and quite probably drugs consuming woman in her late thirties, living in an absolute mess - Long story short, I didn't stay the whole three days. After a copyshop marathon on day one I quickly found another guy driving from Hamburg to Düsseldorf (thanks, Mitfahrgelegenheit.de!) and arrived home in the evening. I guess it was bad a bad apple in HC's database, but I'm not so sure I'll try my luck again in summer for my trip to Ireland.