The following are known Action Replay Codes for Mary-Kate and Ashley: Pocket Planner on Nintendo Game Boy / Color (GB / GBC). These codes were also known as GameShark Codes and in most cases will work on both devices.

Device Compatibility: Action Replay & GameShark

Max Score (Drop To Shop)
0109d8c9
0109d9c9
0109dac9
0109dbc9

Infinite Tries (Drop to Shop)
0100d5c9