Imagine $23 billion in quarters, nickels and dimes. That's how much money Americans drop into vending machines each year. And office worker Chris Dougherty knows why: "Because I'm lazy."

Dougherty, who plunks 65 cents in for a 12-ounce can of Diet Coke, could have done better at the grocery store. But he didn't care. Convenience is king, especially when he wants it now.

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Computer programmer Mike TaRose says he visits vending machines three to four times a week to buy cans of Coke. Like Dougherty, he couldn't care less what he's spending.

"It's really convenient," TaRose said. "If at that moment I need a little lift, it's worth it to me."

Best Buy employee Gentry Sellers is a bit miffed by the high prices, equating the prices at the machines at his workplace to being trapped in an airport.

"Why does a package of M&M's cost $1?" he wondered. "I feel like the man is stickin' it to me every time."

The Real Deal
So are you wasting money in vending machines? Not according to Jackie Clark, the spokesperson for the National Automatic Merchandising Association. She readily concedes that vending machines charge higher prices, but the tradeoff is convenience.

"Where else can you go 24 hours a day, seven days a week and get what you want when you want it?" Clark said. "They're the very same products you get at the grocery store."

Clark says you're actually getting a deal.

"The product out of a vending machine is fresher than a product you'll find at a grocery or a convenience store," she said, arguing that with the constant turnover in product, vending customers rarely go away unhappy. "What's it worth to you?"

"It's not a waste of money if you're hungry, in a hurry and are not overly particular about what you eat," chimes in historian Lynne Olver, editor of The Food Timeline, an independent Web site that tracks eating trends. "Individual, portable packaging makes it easy to eat and run. Anyone who's been driving long distances with kids appreciates the blessing of a vend-only rest stop. Vending machines are welcomed by folks spending long hours in hospitals, students pulling all-nighters during finals and government employees making the most of 15-minute breaks."

Math Time
So what's it worth to you? Time for some simple math.

The most popular snack sold on Earth in a vending machine is a Snickers bar. According to 2006 statistics from the trade journal Automatic Merchandiser, the average vending price for this candy favorite was 70 cents for a 2 ounce bar. At a typical supermarket or discount store, the price is about 55 cents per bar -- a difference of 15 cents.

The savings are more dramatic for salty snacks and beverages.

Second on the list of most popular snacks is the 1.75 ounce bag of nacho cheese Doritos. Each bag costs an average of 78 cents, or 45 cents per ounce. At the grocery store, you can do much, much better.

On average, a 19 ounce bag of Doritos costs $4.50. That works out to about 24 cents per ounce, roughly doubling your value. Sure, the cost escalates a fraction when you haul a small Ziploc bag of chips to work, but it's minimal compared to 78 cents for 1.75 ounces.

Which brings us to Diet Coke, another mega-popular choice. According to the latest survey, the average cost for a single 12 ounce can of Diet Coke in a vending machine is 67 cents. At the store, 12-pack cans retail for an average of $3.75, or 31 cents per can. Cans of soda, however, are often discounted as low as $2.50 per 12-pack, lowering the cost to 21 cents per can.

Turning to breakfast snacks, Kellogg's Pop-Tarts are now in the Top 10 when it comes to vending choices. In 2002, they didn't crack the Top 20. If you select these popular pastries from a vending machine, it'll cost you an average of 81 cents for a pack of two tarts. At the grocery store, a box of eight tarts (four packages of two) will cost you about $2 -- which works out to 50 cents per pack.

In every case, the savings are significant if you think ahead and buy your snacks in the grocery aisle. Common sense dictates that you save even more if you purchase in bulk, or look for sales on the items you constantly choose in vending machines.

Balancing Act
At this point, you may be wondering about nutrition. As in, is any of this stuff good for you? Times are changing. Clark says the vending industry is constantly adding healthy choices for customers (such as fruit, water or SnackWells low-fat cookies), and is working on a new campaign to better label foods in machines so there's little doubt what you're getting.

But let's be honest. The most popular choice among Americans year in, year out is a Snickers bar. That's not an apple. It's a candy bar. Eat a Snickers bar every workday for an entire year, and you might have trouble fitting into those old jeans. So whose fault is it if you walk to a vending machine, don't resist temptation and opt for candy? Clark says don't look at her.

"The vending machine is just a mechanism," she said. "It doesn't make you fat. There's nothing wrong with eating one Snickers bar. But if you eat five, you're going to get fat." Food Comparisons:

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