So, if I have a PC for $5 off 1 Refresh eye drops, and a PC for $8 off 2 boxes, if I get two boxes, can I use both coupons at the same time, thus a $13 savings for 2 boxes? (This would be at Target.)
The short answer: You would need to buy 3 boxes to use both coupons.
The long answer: Having to buy three would be true anywhere, not just at Target. This is the meaning of "one coupon per purchase". You can use one coupon for 1 item and the other coupon for 2 items.
I believe @Francoise is correct. However, I will say that for me at least, digital coupons at Stop & Shop have both applied in the same scenario you mentioned.
@Shopgirl You can only use one paper coupon per item, this is usually mentioned in the teeny print on the bottom of the coupon. BUT since you said it was at target, but sure to check Cartwheel to make sure there is not a Target offer on the item. Those coupons can stack. That is true of any store that offers their own coupons, like Publix or CVS.
