Poor people measure their stuff by its momentary monetary value, rich people measure their assets by their long-term projected intrinsic value. Rich people look for good value, not a good price.
The rich man’s mentality can also work for middle class people if every purchase they make is a long-term well-informed decision, rather than flying with the pop culture of what everyone else is currently buying, wearing or visiting. For example, buy timeless durable unfashionable clothing, buy a used but durable car from which you can extract the best value in the long run, buy products which can be utilised for many purposes, etc.
The rich man’s mentality can also work for middle class people if every purchase they make is a long-term well-informed decision, rather than flying with the pop culture of what everyone else is currently buying, wearing or visiting. For example, buy timeless durable unfashionable clothing, buy a used but durable car from which you can extract the best value in the long run, buy products which can be utilised for many purposes, etc.