The most common and most likely answer to this crossword clue is the 4 plus 5 letter word EASY TERMS
I've seen this crossword clue in The Guardian
E
A
S
Y
T
E
R
M
S
More clues leading to the result EASY TERMS
Buddy explains!

The straight part
We know that "one way to repay debt" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one way to repay debt = easy terms.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.