Keep in mind that it's almost impossible to get hotel reservations during the Swiss Industries Fair, which attracts about a million visitors every spring. Rooms are also impossible to find at Carnival time. Check with the Basel tourist office for exact dates. Hotel rates in Basel tend to be quite high for what you get, because Basel usually fills up its rooms with business clients and doesn't have to rely primarily on tourists.
Note: This information was accurate when it was published, but can change without notice. Please be sure to confirm all rates and details directly with the companies in question before planning your trip.