There are several cheap accommodations in the city center of Maastricht. When you are willing to share a room with several other persons, beds are available from € 28 per night. Single rooms are available from € 30 per night. See for instance:
Fo more regular hotels in Maastricht, you may consult the follwing sites:
All hotels in the city center lay on walking distance from the venue (max 20 minutes walk). Just outside the city center is also possible, but check at which side the hotel is laying if you do not wish to walk too much.
Note that Maastricht has payed parking in the city center and the neighborhoods around the city center.