Hi there,
That's a great question. The answer to that is it really depends on your state as taxes differ from place to place according to their state laws. However? If you are looking for a single line with unlimited talk, text and data (no throttling) then it would be $70 before taxes.
If you get a new device and decide to do the EIP (Equipment Installment Plan) agreement, then the bill would be $90 before taxes for 24 months (or less if you pay off the device earlier). After you pay off for the device in 24 months (or less), then you bill would reduce to $70 before taxes.
Hope that helps!