The most common and most likely answer to this crossword clue is the 7 letter word SUTLERS
S
U
T
L
E
R
S
Buddy explains!
The straight part
We know that "They ply their wares to men in camp" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case they ply their wares to men in camp = sutlers.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 SUTLERS mean?
SUTLERS noun- A person who follows an army, selling provisions.