The most common and most likely answer to this crossword clue is the 10 plus 5 letter word APPEARANCE MONEY
I've seen this crossword clue in The Daily Telegraph
A
P
P
E
A
R
A
N
C
E
M
O
N
E
Y
More clues leading to the result APPEARANCE MONEY
Buddy explains!
The straight part
We know that "Cash someone will come to get" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case cash someone will come to get = appearance money.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.