Vistaprint has free holiday return address labels and To/From gift labels right now. All you pay is shipping. Click on "Get Started" under Your Holiday Headquarters. Then go to "Holiday" on the left and click Labels. There are lots of other good holiday deals as well.
This deal was available last week but it was gone so fast I missed it. Make sure you don't miss it! I'm ordering mine right now.
I think you can only get one of each type for free, otherwise you have to pay. You might be able to make multiple orders, but I haven't checked into that yet.
I got 140 return labels and 140 To/From labels for $4.10!