While it's easy to run out on the day or two after Christmas to snag some deals, been there done that...I have found the best deals normally start mid to the end of the week. I also find that during those first couple days after Christmas I buy stuff that I won't use. With the thoughts of "oh I should pick this up and give it to so and so next year", it usually does not work as well as it does in my head. Mid week the sales drop from 50% off to 75% off. Instead this is the time to stock up on gift wrapping supplies, and not just for Christmas. I usually stock up on tissue paper and tape, and sometimes boxes, bags and wrapping paper! Look for items you can use for birthday presents or other festive events. Also a great time to stock up on those rubbermaid totes, does it really matter that they are red or green???
Great places to find deals would be all the chain drug stores and super stores.
The other day I was able to snag some a 3 pack of heavy duty scotch tape for .50. Also a King size set of flannel sheets for $10 at Target!