by the month
by the month
Per month; at a monthly rate. I'm renting this apartment by the month because I could get my next travel assignment at any time.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
by the month
one month at a time. Not many apartments are rented by the month. I needed a car for a short while, so I rented one by the month.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.