Configure Google Promotions
Witin Google Merchant Center, you can configure promotions that apply for certain products or groups of products. You can enter in promotions either by Category, Manufacturer or SKU, or by all products.
Category or Manufacturer
To enter in by Category Or Manufacturer, select the category or manufacturer that the coupon code applies to, and enter in the marchant promotion, just as it is entered in your adwords settings within Google.
You can apply exceptions to a coupon code for Categories or Canufacturers. This is handy if you are setting a code for All products, but would like to exclude certain Manufactuers. The exceptions dropdown allows you to select multiple Categories or Manufacturers.
You can enter in specific skus for an exception as well. To do this, simply select SKUs from the dropdown, and enter one or several skus in the box. If you press tab, it will allow you to enter another sku. You can also copy a list of slus that are in a row separated by a comma. It should separate the skus when you do this.
Modifying a Promotion
To modify a promotion, click on Modify on the rule in question. When you do this, you will be allowed to change the Promotion ID and excluded Categories or Manufacturers if you need to add or remove any. Then click Update. You can also add or modiy Skus this way as well. To delete a promotion, simply press Delete.