A note on health: None of this takes into consideration the potential costs of any health effects from nicotine addiction, which can be huge. Clearly, the way to save the most money is to kick nicotine entirely. And taking up either habit for the first time isn't going to be good for your wallet.
THE BASICS OF E-CIGARETTES: The devices heat a liquid nicotine solution, creating vapor that users inhale. Smokers like them because the vapor looks like smoke but doesn't contain the thousands of chemicals, tar or odor of regular cigarettes.
Scientists haven't finished much research on e-cigarettes, and the studies that have been done on their safety or ability to help smokers quit have been inconclusive.
Some e-cigarette users, known as "vapers," use e-cigarettes as a way to quit tobacco, or to cut down. Others want to be able to get their nicotine fix in places where regular cigarettes aren't allowed.
But cost is increasingly becoming part of the equation as the average pack of cigarettes around the country tops $6.15, according to the Federation of Tax Administrators.
DOING THE MATH: Smoking is expensive. A pack-a-day smoker can spend anywhere from $1,500 a year in a low-tax state, all the way to about $5,000 in New York City, where a pack can run $13. On average across the country, the tab comes to about $2,250 a year.
The first consideration for someone looking to switch is whether to use disposable models or a refillable. The refillable models promise more savings in exchange for a bigger up-front investment.
Most disposable e-cigarettes say they're equivalent to about 2 packs of cigarettes and cost $6 to $10 apiece, meaning they'd cost about $1,100 to $1,800 a year, for savings of several hundred dollars a year.
The savings are bigger for rechargeable e-cigarettes with disposable cartridges. For an initial investment between $10 and $35 and cartridges that cost $2.50 apiece, smokers in an average state would save almost $1,800 a year.
There's also a more advanced option for the dedicated vaper: a tank system that is filled with vials of flavored nicotine mixture. They cost more up-front, from $35 up to about $200, but $8 worth of liquid can last about 10 days. That promises savings of up to $1,900 a year for the average smoker.
The numbers for an individual smoker can vary significantly depending on their preferred cigarette brand, where they live, the e-cigarette brand they choose and how much liquid nicotine or cartridges they buy at a time.
WHAT VAPERS SAY: "Cigarettes were getting horribly expensive. ... I've thrown endless thousands of dollars away," said 52-year-old Jim Craig, of Salt Lake City, who switched to an e-cigarette last year after smoking since he was 18.
Craig, who was spending upward of $200 per month on cigarettes, said he now spends about $45 a month with his e-cigarette after an initial investment of $200 for a rechargeable battery and refillable tank. He's been able to stash $100 per month in a savings account.
"What we're going to do with that money down the road, I don't know," he said. "I may save it for retirement ... or we might decide to take a vacation or something like that."
THE FUTURE: The savings may not last. While many vapers just pay sales taxes, states like Minnesota and North Carolina place additional taxes e-cigarettes and liquid nicotine. Other states have considered such taxes. Restrictions proposed by the Food and Drug Administration in April also may push costs higher as companies comply with new rules.