[Tutorial] How to setup sale exclusions.

An exclusion is a way to force one sale to first check if another sale is active before applying itself. Exclusions can be tricky, but are very powerful once you get the hang of how they work.
For example. Lets say you have two sales:

1. Buy 2 get a 20% discount
2. Buy 3 get a 33% discount.
   

You don't want the customer to be eligible for both sales.

If they buy 2 you would like them to have a 20% discount, but if they buy 3 or more you would like them to have a 33% discount.  To accomplish this you will want the Buy 2 get a 20% discount sale to first check and make sure the customer isn't eligible for the Buy 3 get a 33% discount sale. You can use an exclusion for this.

First make sure the order to apply is setup so the Buy 3 get a 33% discount sale has a lower number "Order to apply".  This is a very important.  The order to apply is set on the sales overview page.   Using the example above the order of these sales would be:

• Buy 3 get 33% discount - Order to apply = 1
  
• Buy 2 get 20% discount - Order to apply = 2
  

Any sale selected as exclusion must have a higher lower to apply than the sale you are currently creating/editing.

The best way to imagine this is the On Sale module will go through all sales setup on your store one by one applying discounts, adding free products, etc. Using our example the On Sale module will first check if the customer has 3 qualifying products in their cart. If they do the sale will be applied.

On Sale will  then move to the next sale, using the value set in order to apply. On Sale will check if the customer will receive the Buy 2 get 20% discount sale. However, if Buy 3 get 33% discount is set as an exclusion, and the customer is receiving the discount from this sale the On Sale module will skip (or exclude) the Buy 2 get 20% discount. If the customer isn't receiving the Buy 3 get 33% discount the Buy 2 get 20% discount sale will be applied as normal.