My local Wal-Mart had Xtra Laundry Detergent (the 28 load bottles I belive - the small size) on regular price for $1.98.
Combine it with this coupon: Xtra Laundry Detergent or Fabric Softener $1.00/1 Exp. 9-8-10
It can be found in the 6-6 Smart Source.
Bringing your final cost down to .98 cents
My Wal-Mart also had the Tide Trial-Size 1-Load packages in the travel section for .97 cents. Combine with $1.00/1 ANY Tide in yesterday's P+G to make it FREE (I'm sure you all know about this deal though