From my experience, silver reward from adventure give us around 500-600 silver (CMIIW). While on some server might gave us some ointments or cage, on others it might mean nothing to player. Silver value also changing according to needs of player and age of the server. So I'd like to suggest rather than random value, give it some algorithm that calculate silver reward according to current auction situation. For example, lets say the baseline is 5 ointments, the reward can be average price of 5 ointments sold last 24 hours, the number is still tentative but it gives the idea.