[bpeebles]

All phone numbers in the US (actually, North America and some Caribbean islands) are the form AAA-XXX-YYYY, and there's a finite number of AAA (or area codes) that have been issued so far. And some types of numbers are not possible, mostly for historic reasons. I'm not sure how much a block of numbers actually cost in the US, but they're not free. I know a company I worked for tried hard to compress the range of numbers they had so they could give back part of an exchange to save money.

http://en.wikipedia.org/wiki/North_American_Numbering_Plan#N...