What is the word to describe pseudo-elite people who despite being wealthy have low standards of behavior? [duplicate]

Solution 1:

You are probably looking for parvenu:

If you describe someone as a parvenu, you think that although they have acquired wealth or high status they are not very cultured or well-educated. [formal, disapproval]

(Collins Dictionary)

Solution 2:

I offer

ALL FUR COATS AND NO KNICKERS

The British- and Irish-English phrase (all) fur coat(s) and no knickers, or no drawers, denotes ostentatious vulgarity in social life, from the literal sense of a fashionably dressed woman whose appearance covers vulgarity.

Word Histories

In Scotland this is more trenchantly expressed as

“Fur coat, nae drawers”

Word Histories

Solution 3:

In Australia specifically, "cashed up bogan".

There's a term in Australian dialect of English to describe a similar phenomenon: "cashed up bogan", though it's unused outside of Australia. Quoting the Wiktionary page on it:

A person who is unsophisticated or of a lower class background but achieving a high salary, who spends money on flashy or trashy items to fulfil their aspirations of higher social status. The stereotype includes having speech and mannerisms that are considered to denote poor education and uncultured upbringing, which is reflected in their bad taste possessions and lifestyles.

Note that it wouldn't have the connotations of stinginess that the original question asks for, but rather trends towards tacky ostentatious waste.

This term is derived in turn from the word "bogan" which is unique to the Australian dialect, which is used to refer to the uncultured, lower-class members of White Australian society.