Are there any kind of phone apps that allow you text mexico for free?

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Are there any kind of phone apps that allow you text mexico for free?
Are here any smart phone apps that allow you to text mexican numbers fof free. Any that actually work?Viber – Free calls and textingWhatsApp – textingThey take your number to activate the app. Take note that the person you are going to text has the app too. http://answers.yahoo.com/question/?qid=20130410183304AANCrid