I claim the ornamental design for a paint stick dispenser, as shown and described.
FIG. 1 is a front view of a paint stick dispenser, showing my new design;
FIG. 2 is a front view thereof, with the lid shown in a removed position;
FIG. 3 is a front view thereof, showing a usage condition excluding the lid, and showing the paint sticks fully extended, positioned atop an internal piston element;
FIG. 4 is a right side view thereof with the paint sticks retracted and lid replaced; the left side being identical thereto; and,
FIG. 5 is a front view thereof, without the lid and the paint sticks in a fully extended position.