The most common and most likely answer to this crossword clue is the 6 letter word E-CASH
I've seen this crossword clue in The Guardian
E
-
C
A
S
H
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 E-CASH mean?
E-CASH noun- Money that is held, exchanged and represented in electronic form, and is used for transactions over the Internet