These cheats are built into the full version of the game.
They are accessed through the PC in the home office (not the boutique staff-room).

On the PC navigate to the e-mail screen:

Navigate to the 'Write new e-mail' window:

On this screen there are two boxes:

In the receiver/recipient box write the cheat's first value (below listed in the 'contact' column).
In the subject box write the cheat's second value (below listed in the 'subject line' column).

Example (for the money cheat):

The following are the cheat codes as of the initial full release of the game:


It appears that the cheat codes are not case sensitive.