I found two different coupons in Kmart today. Not sure if this was posted.

Buy one 20oz sierra mist (any flavor) get one free
Buy one 2ltr of any sierra mist and get one free

the 20oz at my store was 1.49 and the 2ltrs are on sale for 10/$10, i got (4) 2ltrs and (4) 20 oz free today. HTH