GV does give you a free telephone number but that number ends up forwarding to your land line, cell of SIP telephone number. Your carrier will charge you for that forwarded to connection as they normally would. If its SIP and terminates on a computer there will be no charge like a SIP to SIP call. To me the biggest advantages with GV is that you can keep that number even if you change carriers and that your GV voice mail can be heard or viewed as text. Speech to text technology used isn't perfect but it's nice to have. I forward my GV to my cell and will get SMS notification of missed calls.