The most common and most likely answer to this crossword clue is the 4 plus 3 plus 5 letter word CASH AND CARRY
I've seen this crossword clue in The Times
C
A
S
H
A
N
D
C
A
R
R
Y
More clues leading to the result CASH AND CARRY
Buddy explains!

The straight part
We know that "Warehouse" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case warehouse = cash and carry.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.
Crossword Answer definitions
CASH AND CARRY noun- A means by which someone pays for an item (i.e., does not purchase it on credit) and takes it (i.e., does not await delivery).
- A means by which someone purchases something and sells a future or forward based on it.