The WebShop offers the same items as the mushroom dealer in the game itself, but enables you to purchase items for your character from outside the game, and you will be able to support your favorite content creator by entering a creator code when doing a purchase.
Additionally, you will find special sales in the WebShop which will not be available at the mushroom dealer.
To visit the WebShop simply open https://home.sfgame.net/ in your browser.
You need a character ID to be able to login to the WebShop. More information regarding the character ID can be found here.