Fez doesn't lack variety in its accommodation options. Your main choice is whether to stay in a traditional guesthouse or riad in the colour and chaos of the medina, or in a standard hotel a petit-taxi ride away in the Ville Nouvelle (where budgets tend to go further). Booking in advance is advised during high season, and especially during the Fes Festival of World Sacred Music.
A word of warning if you’re planning to be in Fez during winter: riads can be very cold and they rarely have central heating installed. All have some type of heating, but if you feel the cold you may need to consider a five-star or Ville Nouvelle alternative.