If the user wants to hide the item prices on the webstore and only make it visible to customers are currently logged in, do the following steps
1. Navigate to Setup > Site Builder > Set Up Web Site
2. Go to the Shopping subtab
3. Under the Shopping Basics section, click on the REQUIRE LOGIN FOR PRICING checkbox
4.Click Save
The prices and the add to cart button on the web store will be hidden and show a message Please log in for price to customers who are not logged in.