The last you purchased is the first out. Example: I buy three books: Book 1 = $1, Book 2 = $2, Book 3 = $3. I resell them. Book 3 is the first to leave. The ending inventory is the sum of Book 1 and Book 2. COGS will be comprised of the most recently purchased inventory. Ending inventory will be the value of the oldest items left in inventory once you