thrifty person; frugal person
Describes someone who is careful with money and avoids waste; can carry a slightly old-fashioned or colloquial feel.
My grandmother is a truly thrifty person and doesn't waste things.
He's frugal, so he always manages his money well.
節約家 emphasizes saving money or resources, often with a positive nuance; 始末屋 can have a slightly old-fashioned or folksy tone.
Compound of 始末 (しまつ, 'management; thrift') and 屋 (や, 'person; shop'). The exact historical derivation is uncertain, but the word likely arose from the idea of someone who 'manages' resources carefully.