Author Robert Heinlein popularized the phrase “There ain’t no such thing as a free lunch,” and Yahoo Messenger’s SMS feature isn’t exempt from that statement, though it may seem like it at first. While there is no fee to send a text message from the program, the people to whom you're sending messages could be incurring fees.

The Fine Print

From a sender’s standpoint, the service is free. You type the phone number into Yahoo Messenger, compose your message like you normally would, and press "Send." Off it goes, with no money out of your pocket. The possible hangup is on the receiving end.

If the recipient has a text messaging plan, it simply counts as a message against his monthly allotment. If he does not have a text messaging plan, he'll be charged the individual message rate for their calling plan, typically around 20 cents per message. It’s also possible the person on the receiving end could end up paying for the message out of his data plan, and if they do not have a data plan they could be paying an individual price per kilobyte as well.

If you are using Yahoo Messenger from your phone or tablet to save on your text messages, you don’t get the free lunch either. If you’re sending the instant message from your mobile device using cellular data, it will come out of your monthly data allotment.