Amazon offers the Energizer 2032 3-volt Lithium Coin Battery 4-Pack for $2.83 with free shipping, via the directions below. That's tied with last month's mention and the lowest price we could find by $6.
  1. View Energizer 2032 3-volt Lithium Coin Battery 4-Pack for $3.51
  2. clip the 50-cent coupon on the product page
  3. check out via Subscribe & Save for a final price $2.83
Note: Be sure to cancel your subscription after your order arrives to avoid being billed for subsequent shipments.