Drew writes last year about the ubiquitous Radio Shack/Tandy Battery of the Month Club:

As a kid with very limited funds, one of my favorite Radio Shack promotions was their “Battery of the Month Club.”

Here’s how it worked: You would go into your local Radio Shack, sign up, and be issued a card. Bring the card back each month and redeem for one free standard Radio Shack ‘AA’, ‘C’, ‘D’, or 9-volt transistor battery. The salesperson would mark off that month on the back of the card. Return next month and repeat the process.

This was an ingenious promotion. Batteries only cost a few cents each, so this was a cheap way to bring people into the store. The hope, of course, was that you would purchase expensive electronics gear while you were there. You only received ONE free battery. So unless you got a 9-volt cell, you needed to purchase between 1 to 7 more batteries to power anything.

Read more here.