Well, I won’t be able to brief you on the entire expenditure but I can of course, guide you on the expenses of your phone system. I have been using services.My provider has a certain proposal that if you have per day calling time of over 10K, then they give the Hosted PBX system free of cost. However, you will have to pay the fee of $20/month if the traffic is below 10K/day. However, calling service is not available within India. So, this the approximate cost that will be incurred in your telephony expenses.