dirt cheap

I bought this jacket in the sales. It was dirt cheap.

 If something is 'dirt cheap' it means it is inexpensive and often a bargain.

dirt-cheap fare
格安運賃

buy dirt cheap
飛び切り安く買う、ばか安く買う

get ~ dirt cheap
〈話〉～をすごく安く［超安値で］買う

sell ~ dirt cheap
～を大安売りする、二束三文で売る［販売する］

as cheap as dirt
非常に安い、ばか安い、二束三文の

Labor is （as） cheap as dirt in some developing countries. 
発展途上国の中には、労働力が非常に安い国もある。