SubscriptionDiscount object is used to apply discounts to subscription items, reducing the product price for subscribers.
Reference
Available options: 
subscription-discount The title of the discount shown to customers, typically displayed as a discount code.
Minimum length: 
1- Option 1
- Option 2
- Option 1
- Option 2
The number of billing cycles for which this discount will be applied. After the recurring cycle limit is met the discount will be removed from the subscription.
Required range: 
x >= 1