For creating a ‘Free night stay on a reservation’ kind of a promotion in the OnRes system, follow these steps:

1. Set the Discount Amount to 100% (or any discount amount you like, e.g. 50 for “3rd night half price”)
2. Select “3rd night” to apply discount to
3. You can also choose to repeat the discount for every 3rd night, e.g. for a 6-night reservation, apply discount to the 3rd and 6th night.