The most common and most likely answer to this crossword clue is the 8 letter word TAX-FREE
I've seen this crossword clue in The Guardian
T
A
X
-
F
R
E
E
Buddy explains!

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 TAX-FREE mean?
TAX-FREE adjective- Exempt from taxation