The most common and most likely answer to this crossword clue is the 3 letter word SOU
I've seen this crossword clue in The Times
S
O
U
More clues leading to the result SOU
- Tiny bit of money person has not got left
- It helps keep the salt dry in sweet-and-sour cooking
- Old coin identified by woman on radio
- Resentful about sweet found in bits in hat
- Thus belonging to the upper echelons makes a bit of money
- Individual forks out pounds for old French coin
- Individual cut, minimal amount of money
- Old French coin originally spent on underwear
- A little dough in tart, mostly
- Some miss out small amount of money
Buddy explains!

The straight part
We know that "Tiny bit of money" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case tiny bit of money = sou.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 SOU mean?
SOU noun- An old French copper coin equal to one twentieth of a livre or twelve deniers; one sou is to the livre as one shilling is to the pound.
- Cent; pocket money.
- A thing of the smallest value; a whit; a jot.