1) Go down card isles in stores to find seasonal stickers. Often they are nicely priced and have a good supply.
2) My favorite new creation: If you like the new stickers out that look like Dymo Labels (think the solid label tape with raised white lettering), buy a Dymo Label Buddy. For a few dollars, you can make your own label stickers. The best thing about it is you can buy different colored tape and you get to choose what you say on the tape. Then you can say what you want to say and use it anyway you want.