To determine the average purchase value for a specific time frame, I would begin by calculating the total monetary value of all purchases made during that period. After obtaining this total, I would divide it by the total number of purchases. For instance, if our company sold 1,000 items in the previous quarter with a total sales value of $50,000, the average purchase value would be $50,000 divided by 1,000, resulting in $50. This indicates that the average purchase value per item in the last quarter was $50.