[quote name='PenguinMaster']Been that way for a while. I think you can still use coupon codes with a voucher, so no one should ever be paying for shipping except with other coupon codes being used.[/QUOTE]
Nope... those reward vouchers negate everything. So in fact do the mail-in vouchers and what not, as far as I know, as they are considered coupons, not payment. Only a gift certificate is stackable. So they'll stack with Edge, since everything stacks with Edge, but that's about it.