Shopping Cart Concepts
The following sections describe remote shopping carts in detail.
A cart can contain up to 50 entries. Each entry can represent one or more (up to 999) of the same items. That means that a Product Advertising API shopping cart can contain a maximum of almost 50,000 items.
Many products have a limit on the quantity that can be added to a cart. Sometimes
this is inherent to the product, for example, one-of-a-kind jewelry items. Sometimes
it is a limit set by the vendor, for example, they might set a limit on big ticket
items, such as a motorcycle, of one per customer. If you add an item to the cart
with a quantity that exceeds the maximum allowed,
automatically resets the quantity to the maximum value. No error is generated.
Therefore, you must verify the quantity of items in the cart with the number ordered
to determine if the quantity has been capped. If so, you must notify the customer.
Active and SaveForLater Areas
Shopping carts have two distinct areas:
Active—Contains the items that are ready to be purchased.
SavedForLaterItem—Contains items that a customer has chosen to buy but are currently unavailable, or items that a customer has designated they want to save and buy later.
Available items placed in a shopping cart are automatically added to the Active area unless the customer specifies otherwise. Unavailable items or items in the shopping cart that become unavailable are automatically put into the SaveForLater area. When those items become available Amazon automatically moves the items to the Active area of the shopping cart.
The SaveForLater area can also be used by customers as a holding place for items they are interested in but not ready to purchase. The prices and availability for items in this area are regularly updated by Amazon.