@Orwin -- Cass has said he'll see to the bookkeeping.
@Cass -- The barkeep provides the following information about the bottle of Old Derfingel:
TM:
Although the wine is within a poorly-made vessel, its full potency remains. A single cup of the rare wine provides the same benefits as a potion of heroism. The opaque bottle holds four cups of the intoxicating liquid. If all four cups are consumed in one sitting, it also acts as a potion of extra healing but puts the imbiber in an unconscious state for 12 hours
GP value: 2k.
EXP value if kept: 200.
EXP value if sold: 2k.
Neither Chester nor Aloysius has anything to say about anything else in your inventory (that they haven't already said). That is not to say that they are without value.