VistaPrint.com offers a custom 18x36" vinyl sign banner
for shipping. That's the best deal we've seen for such an item. Choose from 36 ready-made templates. A VistaPrint ad will be present in the bottom left-hand corner. (You can remove the ad for an additional 50 cents.) Note that several other offers will be shown as you check out, but they're all optional.
Of note, other decals and signs are 50% off. Choose from car magnets, window decals, and more.