Of the 3 common inventory methods (LIFO, FIFO, or average cost), which method is used the most and why?

Of the 3 common inventory methods (LIFO, FIFO, or average cost), which method is used the most and why?    What is the actual purchase price of goods?   What is the difference between gross sales and net sales?   With constant price changes in the economy, how does management assign a value to its […]