Economical
Economical (adj) /ˌiː.kəˈnɒm.ɪ.kəl/ US /-ˈnɑː.mɪ-/ /ek.ə-/
careful in making the best use of fuel, money, resources, etc., frugal, cost-effective, parsimonious, thrifty, cheap, sparing, reasonable
I purchased that modern TV at a very economical price at auction.
Antonyms: uneconomical, expensive, wasteful, extravagant
Noun: economy
Adverb: economically