The most common and most likely answer to this crossword clue is the 7 letter word PREPAID
I've seen this crossword clue in The Guardian
P
R
E
P
A
I
D
Buddy explains!
The straight part
We know that "Settled in advance" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case settled in advance = prepaid.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.
What does PREPAID mean?
PREPAID adjective- Paid for in advance
- To pay in advance, or beforehand