Stackable coupon codes at Splenda Store.  Here is a screenshot for your reference.  They apply on clearance items as well.

• 25% off your entire order with code PAIR25 valid through 1/31
• 25% off your entire order and Free shipping with code GIFT25.
• An additional 10% off with code SAMPLE10 valid through 12/31
• Free shipping on orders of $20 or more with code NEWS.
• Automatic free shipping on orders of $49 or more.