How much do I pay per min and per call

It depends on the facility and the carrier at that facility - in some cases, there are savings of over 50%. If you are going to talk a lot, it might be worth looking into. In federal it's a central system that is beneficial if you have a local number. InmateAid gets them for only $5 per month - user/inmate save $45. Check it out by going to Discount Phone Lines to see if you can save too.