It's tempting to start your cell phone shopping by checking out phones, but don't. Coverage is more important. Unfortunately, that's also difficult to assess ahead of time. Coverage maps rarely reveal the tiny dropouts that can make calling unbearable. (The T-Mobile Web site's block-by-block "Personal Coverage Check" is something other firms should emulate.)
As a general rule, however, carriers that allow analog roaming offer the widest possible coverage. Those with only digital coverage tend to do fine in cities -- except for in the Metro underground, where only Verizon (and, with roaming, Sprint) offer service. If in doubt, use the free trials offered by carriers to do your own real-world testing.
The vast numbers of minutes included in most plans mean airtime charges should be fairly predictable in most cases. But you can save a fair amount of money by getting the same carrier as the people you talk to the most. Be wary of charges for data and messaging services, which vary widely among carriers.
Plans for under $40 have become increasingly hard to find. If you're not going to make enough calls to justify spending that much, get prepaid service instead.
-- Rob Pegoraro
