Add 1 or more items to the cart.

Must be an exact match on Product Id, Number(s) or Code.

Single items
format: {item} or {item}:{qty}
to add 1: 123-XX or 123-XX:1
to add 2: 123-XX:2

Multiple items
format: {item}:{qty},{item}:{qty}
ex: 123-XX:100,456-XX:200