Tetherberry is a program you buy that bypasses vzw servers so you can tether without paying either $15 or $30 to vzw depending on your data plan to tether with vzaccess manager. There is a downside, verizon has been auditing accounts with high usage and some have been charged back for the illegal tethering or worse charged .012$/kb which racks up a high bill very quickly as verizon doesn't like it when you steal airtime..
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