£30 - stay longer near the city's exhibition centre west of Frankfurt, at the Hotel Mercure & Residenz, a big modern place with five meeting rooms, Jacuzzi, sauna, restaurant and bar. A 30-day booking works out per day at the price above. Hotel Mercure & Residenz, Voltastrasse 29, 60486 Frankfurt am Main (00 49 69 79260, www.mercure.com).