The usage Limits subtab is where you select how many times a customer can use the promotion that has a multi-use coupon code. You can specify:
One time only – select this option to limit usage of the promotion to one time only per customer.
Unlimited amount of times – select this option to set no restrictions on how many times customers can use the promotion. This is the default behavior.
When multiple sales orders are created from a single estimate, that has a promotion applied to it with one time only usage limits, the usage limits of the promotion are ignored. The promotion will be repeated for the same customer on each of the sales orders created from the estimate. When you make a copy of an estimate rather than creating a sales order, the usage limits of a one time only promotion are respected. A notification informs you that you cannot apply the promotion. For more information regarding estimates, see the Estimates help topic.