Amazon Prime Days ran on July 16th and 17th (at least here, in Canada).
This price jump happened a day before and ended two days later, but this item was “on sale” during those two Prime Days.
I’ve been seeing this scam far too often, especially with food items. Why isn’t this illegal yet?
Put a few items on your wishlist, and watch the fluctuations, even without prime days.
Overall, you save a buck or two on prime days, that’s all.