FIG. 1 is a perspective view of the decorative case for an MP3 player device showing my new design;
FIG. 2 is front view thereof;
FIG. 3 is a rear view thereof,
FIG. 4 is a right side view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof; and,
FIG. 8 is a front view of the decorative case illustrating optional lights and edges visible beneath the front surface. The optional lights and edges being shown in phantom for illustrative purposes only and forming no part of the claimed design.