There are so variables for 727 freighters it's hard to give numbers. Some have takeoff weights over 200,000 pounds but you'll be hard pressed to put more than 50,000 pounds of payload in one unless you're carrying bricks. And I can think of 5 different dash number engines which will make a difference. Round numbers 10,000 pounds fuel flow the first hour, 9,000 hours 2 and 3 and 8 the fourth hour for average weights. If you're up pushing 200,000 pounds, add 1000 to all the above.
The only way I could say a 727-200 is cheaper than a 737-300 is initial cost. After that you will pay more but you get more performance