The new style wood mount stamp cases are awesome and brilliant for more than just storing wood mount stamps in. The full size cases are just $11.95 for a pack of 4 and the half size ones are $8.95 for a pack of 4 (not available quite yet). They are useful for more than just holding wood mount stamps as well, they are also perfect for holding re-inkers, a stack of cards and envelopes as a gift or many other things.
If you are converting your stamp sets from the old style clam shell ones to the new cases, you can print covers for the full size ones here or half size ones here. Alternatively you can decorate the covers with designer series paper or make your own custom covers with My Digital Studio.