Recently one of our customers reached out with an interesting case. He has a few ads in an ad set and as soon as at least one of them gets a purchase he wants to stop the rest of the ads. So the first ads to earn a sale will keep running and getting more exposure while the other ads will wait for a better day:

This rule checks if an ad set has at least one sale. If it has, the rule goes on and checks each ad in that ad set and turns off the ones that have no sales.

Here's a short video guide on this rule:

And don't forget the most important rule: you have questions - you let me know ;) Cheers!