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Get a google voice number.

Get the application.

Send text messages through data and/or wifi.

Plus you can do it all from your computer as well. :)

To lower the bill, I remember actually moving all of my contacts over to google voice and actually canceling my text plan last year; you can have all texts arrive in the application to either reply there or simply do it from your browser.

Saves money and allows you to send off texts a lot faster as well without having to leave the computer.

Oh and I just remembered, this would allow you to text anybody from anywhere, without needing to have a phone. And it's a free phone number to boot. For all that it offers, it can't be beat.
 
If your network lets you send free webtexts from their website then there is probably an app for it. That's how I send free texts.
 
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