Don’t pay to send text messages when you can text your friends for free.
Wikihow.com has an article that shows you how.
First, find out which carrier the recipient uses. There are two ways to use this information.
E-mail
1. Compose an e-mail with your intended text message in the body.
2. Send the e-mail to the e-mail-to-SMS gateway for their carrier. Here are some examples, and the complete list is at the end of this article:
o Sprint Nextel: 1234567890@messaging.sprintpcs.com (1234567890@pm.sprint.com for MMS)
o T-Mobile: 1234567890@tmomail.net (SMS and MMS)
o Verizon: 1234567890@vtext.com (1234567890@vzwpix.com for MMS)
o Cricket: 1234567890@sms.mycricket.com (SMS)
o See bottom of this article for a larger list of carriers
Carrier Website
1. Go to the website of the carrier of the recipient.
2. Look for a form that allows you to send a text message to one of their numbers. You might need to register. Go the website search box or help section and type in "send text message".
So, although you’ll probably pay a monthly fee to receive text messages, you won’t need the higher, more expensive plan because you can send texts for free.
http://www.wikihow.com/Text-Message-Online