A lodging price that can’t be beat: free

ONE of the more effective ways to save money on travel is to stay somewhere free. If you lack a convenient relative or friend, your answer may be a vacation exchange or a hospitality exchange. On the first, you stay in someone else’s home while they stay in yours. On the second, you occupy a spare bed or room in someone’s home in exchange for your promise to offer the same hospitality to others when they pass through your home city. Both methods have enjoyed a surge in recent years as a result of the Internet.

Before the Web, operating a vacation exchange service was burdensome because it required thick directories listing participants’ names.

The directories, mailed to members two or three times a year, quickly became obsolete. Often one contacted prospective exchangees only to learn they had already agreed to an exchange with someone else on the desired dates. Sometimes making a match required dozens of letters. The postage alone was a major expense, and responses were sometimes slow.

The situation changed with the ascent of the Internet. Participants needed to write only one letter describing their homes and apartments, and with the click of a key could send it to 50 potential exchangers. The moment an exchange was agreed upon, the owner removed his home from the list of available properties. When you requested a particular set of dates, you knew those dates were still available because they remained on the exchange club’s Web site. Organizers of exchanges no longer incurred heavy printing and postage costs. For the price of a Web site, one could provide a major service.

In recent years, vacation exchange activity has taken off. If you go to the Google.com search engine and type in the words “vacation exchange,” you quickly find more than 50 organizations offering exchange assistance for modest fees.

You’ll find vacation exchange clubs for senior citizens, for disabled travelers, for feminists, for families and for every other major category. And you will be able to close the deal, requesting and obtaining photos of exchangers’ houses and apartments, and references for people who have exchanged before, which you can quickly verify.

The world of hospitality exchanges isn’t quite as large, but it is substantial nevertheless. These are people who, for many reasons -- because they enjoy meeting others, because they feel a moral obligation, because they want to enjoy reciprocal privileges to stay free when they travel -- are willing to take strangers into their homes for two or three nights or more.

Some charge a modest fee, $5 or $10 a night, to place the transaction on a serious basis. Some offer breakfast to their guests. Others make a point of guiding their guests through their home cities, transporting them into town, introducing them to their neighbors.

And although some expect reciprocal hospitality at a later time, others provide hospitality without requiring anything.

An increasing number of people administer hospitality clubs for modest charges because of the efficiency and low costs made possible by the Internet. They no longer need to print and mail directories. Where there were six or seven such organizations as recently as three years ago, now there are dozens.

To find them, access a search engine, type in the words “hospitality exchange” and you’ll quickly find at least 30 such organizations whose longevity and careful presentations should be adequate proof of their reliability.

Some of the smartest American travelers make use of their services and stay free when they travel -- and enjoy a singular experience while doing so.