I don't know if you've ever noticed this, but sometimes when items go "on sale" on Amazon, they're not actually any cheaper than their regular price, they just look a lot cheaper because the seller jacked up the price so that they could give you "40% off". It happens for Prime Day Deals, and you can bet it's happening for Black Friday/Cyber Monday Deals.
But, there are some ways to know whether you're actually getting a good deal on a product, and the one I use is called Camel Camel Camel. This is a website where you can find the item you're buying on Amazon and see the price history over the past year or so. It'll tell you what the typical price is and what kind of discounts they have had on that item throughout the year.
It's easy to use. Go to camelcamelcamel.com, then copy the amazon URL for the product you want and paste it into Camel's search area and hit enter. It'll bring up that same product with all the pricing information you need to make an informed decision about your purchases.
And if you're stumped as to what to get someone in your family, check out my Christmas Gift Guides for some great ideas for all ages.