The most common and most likely answer to this crossword clue is the 6 plus 4 letter word CREDIT CARD
I've seen this crossword clue in Independent
C
R
E
D
I
T
C
A
R
D
More clues leading to the result CREDIT CARD
- Councillor, correct character to get source of funds
- Eccentric person supports recognition for payment method
- Believe knave perhaps means to pay
- Believe the joker could be plastic
- Acclaim gets comic purchasing power
- Praise paper for pay-off
- What’s often swiped in shops?
- Plastic that can put you in the red?
- Trust one in suit to have means of paying
- Cover of chair getting update, perhaps something red or yellow plastic
Buddy explains!

The straight part
We know that "source of funds" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case source of funds = credit card.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.