what is the difference between base price and nightly price? If these two prices are different for a listing, which one is seen by the guests? What is the function of rule -set?

[Kathy84]

base price and nightly price? 

[Emiel1]

@Kathy84 

The base price is the price you have set for a 1 night stay during weekdays. If you did not set a different price for weekends, it is the same as the nighty price.

The nighty price is also sometimes referred to as the recalculated price per night after a discount is applied (eg weekly or monthly discount) to a booking.

Guest will see all those prices.

A rule set can be used when you want to change listing settings (or add extra requirements) for a specific time period. Once a ruleset is created, it can be applied to the desired time period(s).