Well, since the rebate is only good for one purchase, unless you have a lot of people to send in rebates with separate receipts... the 12 pack is less expensive after rebate for getting 12 bottles of beer.
$5.99 - $4.00 rebate = 1.99 +5.99 = $7.98 for 12 bottles
$12.99 - $7.00 rebate = $5.99 for 12 bottles.
6-packs must sell a lot faster there than 12 packs for the difference.
