Coastal metropolises like Los Angeles, New York, Boston and San Francisco all have their attractions, from sunshine and shopping to clam chowder and cable cars. But while still ranked among the most desirable places to live, hot coastal cities share a common drawback: a dire lack of affordable housing.

For those of us who aren't billionaires, even the charms of Broadway and the beauty of a Pacific sunset might not justify applying most of our salary to a mortgage payment.

High home prices in popular coastal cities appear to be driving a wave of migration to less costly locales, according to Lawrence Yun, economist at the National Association of Realtors, or NAR. Californians are buying up properties in cheaper neighboring states. On the East Coast, Yun said, prospective homeowners are seeking out property in Virginia and the Carolinas.

Last year, moving firm United Van Lines reported that California had a higher number of outbound moves relative to inbound ones for the first time since 1995. For every 44 moves into the state last year, the company handled 56 outbound moves.

States with a much higher number of people moving in rather than out included Oregon, Idaho, Arizona and North Carolina.

Overall, housing affordability nationwide is at its lowest point in 15 years, according to the NAR. In December, the percentage of households in California able to afford a median-priced home stood at 14 percent, according to the California Association of Realtors. New York City, Boston, Washington, D.C., and increasingly, South Florida, according to Yun, are also progressively unaffordable. The most affordable markets, by contrast, tend to be in the Midwest.

If you're living in one of the places on the most-expensive list, take heart. There are plenty of places in the United States where homes are still quite affordable. With real estate markets in some popular relocation venues showing signs of slowing, this might be a prime period for home buyers to plan a move.

But don't pack up your belongings just yet. Here are some things to consider when choosing a new place to live:

Cast a wide net ... at first
When contemplating a move several hours or even time zones away, the possibilities initially can seem endless. For those living in the nation's most expensive ZIP codes, almost anyplace looks like a comparative bargain.

Start with an open mind. Talk to friends and family about where they live or wish they lived. Compare prices in Manhattan, N.Y., and Manhattan, Kan., using Web sites like Realtor.com or Yahoo Real Estate. Read articles and books that rank best places to live. Often they'll point to unexpected locales. One list ranked Las Cruces, N.M., and Athens, Ga., among the best destinations for retirees. Boise, Idaho, meanwhile, topped a Forbes list of places to pursue a business or career.

Online quizzes can also be an entertaining option. Two to try are Sperling's Best Places and Find Your Spot. The sites ask you to specify preferences for locations based on qualities like climate and cost of living, then return matches to corresponding towns and cities.