"willingness to pay" for meaning of affordability?

I’m looking for research paper(or wikipedia page, whatever) about willingness to pay for something in general. Since I noticed the significant difference of "willingness for paying" between countries, for example, Japan and the US, with consideration of average disposable income.

Accounting to wikipedia, "willingness to pay" is described as:

willingness to accept (WTA) is the minimum monetary amount that а person is willing to accept to sell a good or service

So, the meaning of this term is generally used for a good or service. Not as whole or general sense.
In this case, what English word can I use to describe the "willingness to pay" instead?