Great question, kb12M! When paying off a device payment agreement, you will no longer see a monthly charge for your device. If you happen to be located in AL, AZ, CO, IL, NM, ND, or SD, tax for the phone has also been split up into small monthly payments each month too. Should you live in any of those states, you will also see a small decrease in your tax rate after paying off your agreement.
I would encourage you to review your statement via My Verizon here: http://vz.to/34S7U6H for a more specific number as to how much you are paying monthly for your device. Please expand the charges next to the mobile number in question, and you will see a line for Device Payment Plan under the section for Monthly Charges. You may also use the button at the top for View Bill PDF if you prefer to review your bill in PDF format. Does this help answer your question?