That's not handled well by the mainstream of the profession. Although, behavioralists would probably say that you're using simple heuristic rules to reduce the complexity of your personal finance problem.

The Austrian tradition allows for you to view your free sats as a different good than your earned sats, similar to the example I gave with water.

There are only a few strict rationality assumptions that are fundamental to economic theory. We basically just require that people can state which thing they prefer when presented with two options.

Some particular theoretical results may rest on other simplifying assumptions. For example, if you view A>B and B>C, then you must view A>C.

I think people are often surprised at how minimal the assumptions in economics really are.