The selling price is direct from your settlement sheet. The underlying assets sold may have a current value of zero if fully depreciated.The equipment sold is used. Under a perpetual inventory system, journalize the entries required for these transactions. When we're talking about the gain or loss of the sale of an asset we need to be looking at net book value at the time of the sale. Businesses must record sales tax collections and payments for organized and accurate books. The journal entries for the above transactions under a perpetual inventory system are as follows:1.