frugal person; thrifty person
Refers to someone who is economical and careful with money; not necessarily stingy, but prudent in spending.
He is a frugal person and doesn't waste money.
節約家 focuses on cutting back expenses, whereas 経済家 implies overall financial prudence.
Compound of 経済 (economy, thrift) and 家 (person with a certain trait). The exact historical derivation is uncertain, but the word follows a common pattern for describing a person with a particular quality.