Because it's cheap, and getting cheaper all the time.

BBC: Coal resurgence calls undermine clean energy commitments

Coal has dominated the U.S. power industry for so long because it's a cheap and abundant domestic resource.

MSN: Coal producers find themselves in a hard place

Rodney Johnson, president of HS Dent Investment Management, recommends Ford because it's a cheap stock.

FORBES: Ford's A Buy

"It's cheap, simple and protects wonderfully without side effects because it's a totally inactive protein, " she said.

BBC: Vaccine hope for lethal toxin

Of course, just because something is cheap doesn't mean it's a good investment.

FORBES: Switch Hitter

The case also is unusual because Zoloft has had cheap generic competition since 2006, so it's no longer advertised, and little brand-name Zoloft is sold.

WSJ: Pfizer disputes suit claiming Zoloft doesn't work

Because U.S. citizenship has tremendous value, and we shouldn't give it away on the cheap.

CNN: Path to citizenship should be a long hike

Low Disruption means leveraging the Cheap Revolution for all it's worth to introduce products and services that are stunningly cheap yet make money because their cost basis is so low.

FORBES: Magazine Article

Mr. HOGAN: The cheap dollar is part of the process, but it's not always to be blamed because there's not a constant relationship.

NPR: Assessing Wall Street's Shaky Week