Saarbruecken offers many hotels and hostels in all categories.

Hotel Ibis (50 meters. Single room: 44€)
Europa Hotel (250 meters. Single room: 49€)
Mercure Hotel (800 meters. Single room: 80€)
Hotel zur Klause (900 meters from the venue. Single room: 43€)
Hotel Stadt Hamburg (900 meters. Single room: 63€)
Motel one (1000 meters. Single room: 79€)
Hotel Madeleine (1100 meters. Single room: 65€)
Hotel Fuchs (1100 meters. Single room: 82€)
Hotel Crystal (1300 meters. Single room: 69€)

„Nauwieser Apartements“ (1500 meters. Single room: 62€)

If you need or wish a free place to stay for the duration of the conference, check this: Couchsurfing.com