‘One-Time Use’ Coupons are the bigger discount coupons that can only be used once. These coupons can only be downloaded once per year, and must be used within 10 days of downloading (i.e. They have an expiry date, 10 days from the day of download).
These are generally the coupons that have more value, and will save you more than the entire cost of membership after 2-3 uses. These are very exclusive, and course owners cannot afford to give these discounts out every day!