From Webkinz Insider Wiki
What Is KinzStyle?
Prior to March 2013, members who purchased Webkinz clothing item (a physical item) for their plush pets from a retail store could enter the associated code in the code shop on Webkinz. The code gave the members a virtual edition of the clothing item and a shopping bag. The shopping bag could be dropped into their webkinz rooms, giving them access to the special shop and other clothing items.
In March 2013, the shop became purchasable for 10,000 (less with a coupon) in the W-Shop for Deluxe members, giving Deluxe members unlimited access to the shop and its items. When Deluxe members buy the shop, the icon appears in their "Map Only" section of their dock. They can drop the icon onto their customizable Map of Kinzville. 
Members can still purchase physical clothing items, use the code and enter the shop the original way, but either way the shop is accessed (via the clothing code or via the Kinzville Map), the clothing items listed above no longer appear in the shop.
KinzStyle Code Shop
For each clothing item code you enter you will get two things: An exact virtual replica of that item for your pet to wear in Webkinz World, and a shopping bag for the KinzStyle shop.
If you are not a deluxe member and do not have the shop on your Kinzville Map, then that shopping bag allows you to get into the shop and look around. You can use the bag as many times as you like to go in and look, but once you actually buy something, the bag will have been used, and you cannot get into the shop again until you enter another code.
As of March 2013, Deluxe members have unlimited access to the shop via a Deluxe-only Kinzville Map store.
List of Plushie KinzStyle Items
To see pictures of the Plushie KinzStyle items visit Plushie KinzStyle Clothing.
List of Virtual KinzStyle Items
To see pictures of the Virtual KinzStyle items visit (Picture Gallery) KinzStyle & KinzClothes.
Note About Sets
Important note about clothing sold in "sets": If you buy an outfit for your plushie that has more than one piece to it (Witch Costume, Cheerleader Outfit, etc), entering the code will get you virtual copies of BOTH items of clothing, as well as the KinzStyle shopping bag to get another piece. If you buy a single item for your plushie, entering the code will get you a virtual copy of that one item and a shopping bag. If you would like to buy one of these "sets" in the virtual store, it will take TWO shopping bags because, unlike the plushie clothing, the virtual items are sold separately.
- ↑ When the shop became a W-shop item, some clothing items that were previously available disappeared (3D Glasses Baseball Uniform Helmet, Baseball Uniform Jersey, Baseball Uniform Pants, Basketball Jersey, Basketball Shorts, Bunched Sleeve Blouse, Cheerleader Skirt Cheerleader Tanktop, Cute Blouse, Gathered Lime Pants, Holnwon Golf Cap, Holnwon Golf Pants, Holnwon Golf Shoes, Hot Pink Studded Shades Pumpkin Costume, Springtime Dress, Webkinz Sports Shorts, Webkinz Sports Top, Witch Hat, anad Witch’s Dress.