What is the best formula of price of the product depending on amount. I mean "best" in psychological, marketing, stock rotation, profit maximizing, etc sense (any of them or all together, if possible).
Say, I often see that prices on Coca Cola bottles growing not as fast as volume of them.
I sure there is the best formula, invented by psychologists or derived empirically then proved in use.
Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.
I think your expectation that a "best" formula exists is very unreasonable.
There is no "best" car design, there isn't a formula to design the fastest airplane with total weight $x$ and there is no easy formula that will give you the best price in general situations.
Sciences have a lot of unsolved optimization problems. Economics, psychology and most sciences involving humans have a lot of seemingly unknown variables, further complicating things. So while there are some principles which you can base your pricing strategy on I have never heard any reasonable person claim that a general best price mechanism exists and I don't think it does.
