The most common and most likely answer to this crossword clue is the 7 letter word SHOPPER
I've seen this crossword clue in The Daily Telegraph
S
H
O
P
P
E
R
Buddy explains!

The straight part
We know that "One may want to know what’s in store" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case one may want to know what’s in store = shopper.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 SHOPPER mean?
SHOPPER noun- A person who shops.
- A free local newspaper containing advertisements for local shops etc; sometimes includes discount coupons.
- A kind of bicycle suited to riding short distances.
- A plastic shopping bag.