Head to Target and get a nice deal on Purex Detergent this week. You can get the huge 100 0z bottle for only $4.24 each after gift card promo.
Buy (2) Purex Liquid Laundry Detergent (100 loads) @$6.99/ea = $13.98
Use (1) $0.50/1 Purex Laundry Detergent = -$0.50
Get Back: $5 Target Gift Card
Final Price: $4.24 each or $8.48 for both