UPDATE: As of June 2017, we now generate URLs that apply the coupon code automatically when a pre-order customer clicks the link.
Project creators can now generate coupon codes that backers can apply to add-on items or pre-orders. The codes can give backers a flat discount on add-on items and pre-orders.
Creators can use the codes as a promotional tool to offer discounts to drive sales. For example, you can create a coupon that grants backers a $5 discount on add-ons to celebrate survey day. Or, if you release new add-on items after you’ve sent out surveys, you can announce the new items in a project update and offer a coupon code to encourage backers to return to their surveys. 
Each project has a coupon management page where you can create new coupons, view a list of existing coupons, and see which backers have used coupons.
Coupons are useful for running new promotions for your pre-order store. You can send a coupon code to your email list, or test out different marketing channels by promoting different codes on each channel to see which one gets used the most.
We’re working on enabling more types of coupons in the future. You can find the coupon management page in the add-ons section of your project.
Happy promoting!