If you are curious how a piece of Item Mall gear will look once equipped on a character, all you have to do is open up the Item Mall interface by pressing alt+b or clicking on the coins icon in the upper right corner of the screen.
From there, press the Preview
button then left click on the Item Mall gear in question.
This will change the character's appearance to match the look as if the selected IM item was equipped on the character. You can use the rotation and Reset buttons at the bottom of the window to view these changes from different angles or the default view.