Get 1 Free

[michael_s]

This contribution allows you to promote a product by giving a free product when
the customer buys a specified number of the product you are promoting. This is
commonly used for a "buy two, get one free" promotion, but it is more versatile
than that:
* The qualifying quantity of the product you are promoting can be any number,
including one.
* The free product can be the same as the promoted product or any other product
in your catalog.
* You can limit the free product to one per order or any number that you wish.
* Like specials, you can set a date for the offer to expire.
* You can have any number of products in this promotion with different
requirements for each.

The free product is automatically added to the customers shopping cart when they
purchase a qualifying product in the qualifying quantity (or more.) The free
product is removed when the customer removes the qualifying product from their
cart or reduces the quantity below the qualifying quantity. The customer cannot
increase the number of free products without qualifying for them. It's designed
to be fairly foolproof.

The support thread is here:
http://forums.oscommerce.com/index.php?showtopic=255288

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