The ornamental design for a bill payer's desk, as shown and described.
FIG. 1 is a front perspective view showing the desk in a closed position.
FIG. 2 is a front perspective view showing the desk with the horizontal writing surface extended; and,
FIG. 3 is a rear perspective view showing the desk with the horizontal writing surface extended.
The desk in which the design is embodied is intended to provide easily accessible file drawers, a writing surface, a magazine bin, storage accommodations and a letter carrier.