The most common and most likely answer to this crossword clue is the 8 letter word NICKNACK
I've seen this crossword clue in The Times
N
I
C
K
N
A
C
K
Buddy explains!

The straight part
We know that "a thing of little value" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a thing of little value = nicknack.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 NICKNACK mean?
NICKNACK noun- A small ornament of minor value.