Definition
When a seller includes an additional item at no cost with the purchase of another product.
赠送额外物品，免费附加
If you buy this TV, I will throw in a sound system for free.
如果你买这台电视，我会免费赠送一套音响系统。
The chef will throw in a complimentary drink with the special meal at this restaurant.
在这家餐厅点这道特别餐点，主厨会免费赠送一杯饮料。
When you subscribe to this magazine, they will throw in a free book as well.
当你订阅这本杂志时，他们还会免费赠送一本书。