If you have to ship gifts to people this holiday season, consider requesting free Flat Rate boxes from the USPS. The boxes are free, but you still have to pay shipping (I think it starts at $4.95 and goes up to $15 depending on size). I'm not really sure - I know the large ones are either $12 or $15.
Click this link HERE to request your 5 pack today (or 4 pack if you want a variety). They'll deliver them to your door for you. While you are there, consider purchasing your stamps online too (you know, for all those free Christmas cards you just got!). I personally like this service. Apparently I'm too lazy to go 1/3 of a mile up to my post office to purchase stamps. Stamps to have a $1.00 shipping charge. But you can pick out the ones you want (most years, my post office is out of the Christmas ones).