A shopping list contains a list with all the items that need to be purchased, and it is meant to reduce the time spent in a shop.
There are numerous software applications that offer users the possibility to easily create their own customized shopping list, enter all the items as they come to mind, then print it right before going to the shop.
Additionally, these apps might also offer suggestions as to the items one needs to acquire, or they can also predict them based on previous shopping lists.
There are also some utilities that help users to group the items according to the aisle they are located in, and might even suggest the lowest prices for various items.