For example, I own a Verizon Samsung Galaxy Nexus with a (grandfathered-in) unlimited data plan. I also own an AT&T 3G iPad. Instead of paying for data on my iPad ($30 for 3GB), I pay Verizon an extra $20 for the ability to tether my iPad to my Nexus when I need an on-the-go Internet connection.

Tethering often costs more than just paying for additional data, so use caution; review your data plan beforehand to verify that this tethering trick is a good idea.

These are merely a few ways that you can use less data and (hopefully) pay a lower wireless bill. Go forth, use less data, and share your creative tips for circumventing cellular data caps in the comments!