Originally Posted by
AlienInTheFatherland
Like anywhere in Germany, hotel prices in Dortmund will spike during a trade fair.
I consider Dortmund to be a bit of a dump, so in your shoes I would probably stay somewehre nicer like Düsseldorf and take the train to/from the fair each day.
Dortmund is a dump, no question. Always try to avoid it. Nevertheless traveling from Düsseldorf (even as there are nice hotels) to Dortmund every day is not convenient, even with robbery prices. Essen is slightly better, but if budget allows I would stay near the Westfalenhallen.