The 7 events observed produced no real discount.
At $89.99, the price sits 43% below the usual price of $158.15 (a calculated reference value). It is the lowest ever recorded, and it has never been lower in the past 365 days. The year's high reached $276.03.
The price is volatile, changing every 11 days on average. Over the year, only 2 drops below the usual price were observed, with a median length of 24 days. The current drop has lasted 24 days, so it has reached its typical length. The 7 sales events observed (Prime Day, Black Friday, etc.) brought no real discount.
Waiting for the next event probably won't help. The realistically reachable low price was $139.99, hit twice and held for 57 days in total. Today's price is well below that mark, and nothing suggests it will last long.