It seems no one knows just when the word “staycation” entered the vocabulary, but it’s popping up more and more as Americans pinch pennies.

The idea is to stay home on your vacation, saving the money you’d otherwise spend on airfare, gasoline, hotels, restaurant meals and all the other costs that can total thousands of dollars for a typical two or three-week family trip.

But there’s a dilemma: Lots of resorts, cruise lines, air carriers and beach rentals are bargains this year, as the travel and vacation industry struggles to lure thrifty vacationers.

The online travel agencies Expedia (Stock Quote: EXPE), Priceline (Stock Quote: PCLN) and Orbitz (Stock Quote: OWW) are full of good deals. You might never get a better opportunity to take that Alaskan cruise.

How do you choose?

One way is to start with what economists and financial types call the “time value of money.” In layman’s terms, that describes what a dollar saved today could be worth in the future.

Suppose staying at home saves you $3,000. The average five-year certificate of deposit pays about 2.2 percent, according to the survey. So you could have $3,345 after five years by investing in a CD instead of going on vacation, the Savings, Taxes, and Inflation calculator says.

Put that sum into a good stock mutual fund returning, say, 7 percent a year, and you’d have $4,208 in five years, or $11,609 in 20 years.

That might be enough to cover several months of retirement, assuming you’ll have some other resources like Social Security.

So, would you rather take a trip this summer or retire a few months earlier?

There’s no correct answer of course. It’s an individual choice.

A big factor is figuring what’s most appealing about your vacations. If travel is the big thrill, it’s probably worth paying for. But if most the pleasure comes from simply not having to go to work, you can get the same enjoyment at home.

A staycation looks more appealing if you make it more like a vacation and less like rattling around the house with nothing to do.

People who have done it say the key is to prepare just as you would for a trip.

• Pay the bills ahead of time, as if you’re going to be out of touch for a while.

• Foreswear all chores. Nothing can wreck a staycation faster than a nagging feeling you should be painting the guest room.

• Plan activities. If you spent a fortune to go to Paris, you’d have a list of things to do. You can do the same at home. After all, some out-of-towners will spend a bundle to visit tourist sites in your backyard.

• Don’t get too stingy. If you’re forgoing airfares and hotels, you probably can afford some nice dinners out.

Of course, this doesn’t have to be an either-or decision. You can always split the difference, traveling for half your vacation and staying home for the rest.

—For more ways to save, spend, invest and borrow, visit