Course tickets allow you to sell tickets covering all dates and times in an entry. If you accept attendances mid-course, you may want to use this feature to automatically reduce the course ticket price as each date passes on the entry.
Firstly head over to your selected entry via Edit Entry, then Tickets & Costs.
Select the checkbox titled Course ticket. Make sure you've saved your entry with at least two dates before creating the course ticket.
After selecting this, you'll see a setting titled Discount past dates, as shown below.
The number entered is the value you want your course ticket to decrease for each date that passes on your course.
In the example below, the course ticket is £100. There are ten dates for the course, with a discount of £10 for each date that passes. For example, on the fifth date of the course, the ticket would cost £50 to join the remaining course (5 x £10 discounted from £100).