This paper gives a framework of real-time pricing based on networked power demand estimators, that is, systems estimating total power demand by exchanging information with their neighbors. The problem considered here is to design the estimators and a power price controller such that the total power demand tracks a given reference input under a constraint on the range of the power price. As a solution to this problem, we propose consensus-based estimators and a proportional and integral controller, and derive conditions for the gains to achieve tracking the reference input. The result is demonstrated by a numerical simulation.