Custom toll free numbers have become as hard to get as good domain names. The new 855 toll free area code means businesses have another chance get the easy-to-remember “phoneword” they want.

As most ad writers will tell you, nothing makes people’s eyes light up like the word “free.”

Hence the popularity of toll free calling, in which the party receiving the call bears the full cost of the call. The first toll-free numbers were pioneered by phone companies and travel bureaus in the 1960s, but the idea spread to other industries in the 1980s through AT&T, which then had a monopoly on 1-800 numbers.

It wasn’t until the 1990s that someone came up with the idea of creating numbers that corresponded with phone dials or keypads to spell a business or product name. The best-known custom toll free number is probably 1-800-356-9377 — also known as 1-800-FLOWERS.

Although custom toll free numbers are often called “vanity numbers,” they are based not on corporate egotism but on cognitive research. Studies show that people are far more likely to remember a word than a number, so a custom toll free number is ideal for use in print, radio, TV advertising, online ads, and in signage.

How popular are these “phone word” numbers today? A highly desirable custom toll free number such as 1-866-LAWYERS or 1-888-NEWLOAN can be worth many thousands of dollars. In fact, in a bankruptcy is often its vanity toll free number.

The process of obtaining a good custom toll free phone number is similar to the process of getting a good domain name — and both are becoming more difficult every day. Toll free numbers are portable, so companies are highly unlikely to stop using a vanity number that’s bringing them business. Some large non-profits, such as the Red Cross, have been able to get their custom toll free numbers assigned to them permanently by order of the Federal Communications Commission.

Toll free numbers are assigned through several hundred Responsible Organizations (RespOrgs) that have access to a database of toll free numbers. RespOrgs include both telephone companies and independent companies, some of which specialize in toll free numbers and vanity numbers for business use. There are even RespOrgs that will negotiate on a customer’s behalf to get a toll free number currently assigned to another organization re-assigned.

Just as the best “.com” and “.biz” domain names have been quickly snapped up, the supply of vanity toll free numbers in the existing toll-free area codes (800, 888, 877, and 866) is pretty much exhausted. As a result, the Federal Communications Commission has authorized the October 1, 2010, roll-out of a whole new toll free area code: 855.

Chris Rugh, a veteran of the custom toll free numbers industry, calls the advent of 855 “the most important intellectual property release in the toll-free industry of the past decade.”

Businesses that have waited in vain for a “phoneword” with a popular 800 prefix to become available will now have a shot at getting the desired custom toll free number with the 855 prefix. And, just as with domain names, there will be some businesses willing to pay to keep a competitor from getting at a good phoneword.

If you’re looking for a vanity toll free number to match a business name, product name, or domain name, this is the time to start exploring possibilities in the new 855 area code.