Redenvelope.com is offering free shipping when you use your Mastercard.
Two steps required to redeem:
1) enter MCSAVINGS in the Promotion Code box on the Shopping Bag page
2) choose MasterCard® card as your Payment type on the Order Summary page. Please note the cutoff for 2-Business Day shipping for delivery byis Thursday, December 20, 3pm PT / 6pm ET.
Alternatively, use code NOEXCUSES for a free 2-day shipping upgrade. Also expires 12/20.