If you're just buying things without knowing the general price of them, then Black Friday is the least of your problems. And no I don't mean just checking Camel^3, which is also thoroughly gamed.
Coupon codes, exclusive pricing (business, prime, etc), different product listings - all not reflected in the history AFAICT. Never mind that for many products, Amazon has consistently high prices. CCC is handy, but it's just one data point.