Payments
Under Payments, use Course Fee to set how much participants will pay to sign up for the course.

Course Coupons are for discounting the price of the course with either a set amount, or a percentage.
*Disable Coupon Stacking would mean someone cannot use multiple coupons, only one can be applied at a time. If this box is not selected, people could use multiple coupons to furtherdiscount the course price.
*Coupon codes aren't display anywhere, someone would only know the code if it was shared with them.
Select + Create Coupon.

Determine name of coupon, how much the discount is going to be, the code they will type in at the time of registration to receive the discount, how many times the discount can be used total, and when the coupon will be active. If you do not setup a coupon date, the coupon will not work. Select start date first, then end date to ensure you've selected the desired date range. 
Coupon codes are not available anywhere for prospective participants to see. If you want to someone to use the coupon, simply share the code for them to type in at the time of registration.