| Bubble wrap is an advantageous packing material for small and/or fragile objects. It's very lightweight and will add little or nothing to shipping costs. Although the bubbles will pop if significant pressure is applied directly to a single bubble, the material as a whole holds up very well against the broad, oblique impacts typically inflicted by the post office.
To test the effectiveness of bubble wrap, try the following experiment. Find a few spare CD jewel cases. Wrap one in bubble wrap, one in plain paper, and leave the third uncovered. Drop them onto a hard surface from a height of a few feet. The unprotected jewel case will almost certainly crack and possibly shatter, sending fragments of jagged plastic in random directions. The paper-wrapped one won't go flying all over the place, but will probably suffer some hairline fractures. But the bubble-wrapped should remain unscathed, the brunt of the impact absorbed by dozens of small air bubbles acting as miniature shock absorbers.
If you're not inclined toward the recreational uses of bubble wrap, it can be reused many times and thus becomes very cost-effective. And if you do decide, in a fit of childish exuberance, to pop the bubbles, you still have a perfectly good sheet of plain plastic wrap to keep your food from drying up in the refrigerator. | 
