The ornamental design for light up retail display stand, as shown and described.
FIG. 1 is a perspective view of a light up retail display stand according to our new design in a lit state;
FIG. 2 is a top plan view thereof, shown in environment;
FIG. 3 is a left side view thereof, the right side view being the same;
FIG. 4 is a left side view of FIG. 1, shown in an unlit state; and,
FIG. 5 is a top plan view of FIG. 1, shown in environment.
The broken lines including the renderings of sides of the light up retail display stand, the surrounding additional fixtures, and the portrayal of a glow in the lit state, illustrate environmental structure and form no part of the claimed design.