Do you know what the most expensive iOS app is? And what is the best way to get the best discounts on apps? And is there a best time of year or day to get discounts from Amazon or the App Store?
No, no and no.
Traditionally mid November is going to be a decent bet for apps to get discounts with Black Friday and Cyber Monday being the best times.
Around major US holidays such as Memorial day is also possible.
But there are zero guarantees with any of this.
As for Amazon, Prime Day is meant to be decent, but I've never found anything useful from Amazon then.