'Frugal' is one possible answer.
No. The word thrifty is an adjective. The adverb form is "thriftily" (an a thrifty manner).
My dad was a thrifty spender. He was known for being thrifty.
Thrifty
The word "thrifty" can only be applied to humans.
The noun form of the adjective thrifty is thriftiness.The word thrifty is the adjective form of the noun thrift.
Thrifty is an adjective. It could be a synonym to one word, such as sparing or saving, and an antonym to another word, such as wasteful.
Thrifty
*an antonym thrifty.
A positive word could be bargain, or thrifty.
"Thrifty". See this line from The Merchant of Venice: "Well, Jessica, go in; perhaps I will return immediately: do as I bid you; shut doors after you: fast bind, fast find; a proverb never stale in thrifty mind." It's English, so it should come as no surprise that "thrifty" means "thrifty".
positive
She was thrifty with her money, always searching for the best deals and saving wherever she could.