smart investing tips

They look like cigarettes, feel like cigarettes, taste like cigarettes - and, smokers will tell you - satisfy the craving for a smoke.

But electronic cigarettes, or e-cigs, don't have any of the offensive smoke that's so harmful to health. Instead, they feature an odorless vapor in which nicotine is delivered to the user. And they're sometimes allowed in public places where cigarettes are banned.

Studies show e-cigs make smoking healthier for smokers and those around them, while also helping smokers quit.

Plus, e-cigs cost about half as much as regular cigarettes.

Big tobacco continues to place bets that electronic cigarettes can keep the tobacco industry and its annual sales north of $750 billion and growing.

Altria Group Inc. (NYSE: MO), the world's biggest tobacco company and parent company of Philip Morris USA, is the last of the three major U.S. tobacco firms to get into the e-cigs game.

"There is no denying that adult tobacco consumers have shown interest in it," Marty Barrington, Altria's CEO, told investors during an earnings conference call last week.

Thanks to increased health awareness, as well as the introduction of several taxes which have led to the price of packs more than tripling in some cities, cigarette sales began declining over15 years ago and continue to do so, falling 6.2% in the first quarter of 2013.

Even though e-cigs were introduced almost 10 years ago, they are just starting to take off. Sales in the U.S. totaled $500 million in 2012 and are expected to double to $1 billion in 2013.

And a recent study by the Centers for Disease Control and Prevention found that 21% of adults who smoke regular cigarettes had used e-cigs in 2011, up from 10% in 2010.

So, now that e-cigs are growing more popular, what's the best way to invest in them?