What information do farm magazines ask for in exchange for free subscriptions?
Farm magazines offer free subscriptions in exchange for detailed information about your farming operation, including how many head of cows you run and how many acres you farm. The speaker stopped filling out these forms, preferring to pay for the subscription so they don't have to know his operation.
Les explains that in the farming area, farm magazines will give a free subscription if you fill out all the information concerning your operation, such as how many head of cows you run and how many acres you farm. He says he has quit filling them out and would rather pay for his subscription so they don't have to know. This fits the larger point that the powers that be—insurance companies, financial institutions, magazines—already know everything about people, and he imagines the same data gathering happens in every other profession or occupation.