Next HoT sale
Sales are never announced beforehand, but they’ve happend preceding several (but not all!) of the new Living World episodes, and one of those are coming soon, likely sometime end of april or early may.
Also, check the official list of retailers on the website, and see if any of them are having a sale. At least Amazon and one other have sold it for less than full price at … as far as I can tell, random times.
My guess is the first Tuesday in May