I aim for the same approach. Yes, you have to make sure they are real sales. An easy if imperfect way is to jot down the current price when you first want to bu

I aim for the same approach. Yes, you have to make sure they are real sales. An easy if imperfect way is to jot down the current price when you first want to buy the thing, then compare what you see on “sale.” (As someone else suggested, camelcamelcamel.com is great for Amazon price history.) Used prices also tend to go down during sale periods proportionally.