The most common and most likely answer to this crossword clue is the 3 plus 4 letter word OLD ROPE
I've seen this crossword clue in The Guardian
O
L
D
R
O
P
E
More clues leading to the result OLD ROPE
Buddy explains!

The straight part
We know that "you’ll easily get cash for i" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case you’ll easily get cash for i = old rope.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.