Black friday in general is pretty lackluster lately, but keep in mind that you're looking for deals on items that don't really experience the seasonal variability that other consumer products do. People (generally, this sub aside lol) aren't putting HDDs under the christmas tree.

Internal 5TB 2.5" drives are expensive for their capacity and don't fit in many consumer 2.5" bays due to their excess height. You're better off getting a 3.5" external that you can shuck when you later upgrade cases. It'll also get you more capacity for your money.