The most common and most likely answer to this crossword clue is the 8 letter word TUPPENCE
I've seen this crossword clue in The Times
T
U
P
P
E
N
C
E
More clues leading to the result TUPPENCE
Buddy explains!

The straight part
We know that "not worth much" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case not worth much = tuppence.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 TUPPENCE mean?
TUPPENCE noun- Two pence (in pre- or post-decimalisation currency).
- Opinion.
- (usually childish) Vulva or vagina.