The most common and most likely answer to this crossword clue is the 7 letter word ADD-ONS
I've seen this crossword clue in The Guardian
A
D
D
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O
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Buddy explains!
The straight part
We know that "extra charges" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case extra charges = add-ons.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 ADD-ONS mean?
ADD-ONS noun- (sometimes attributive) Something which can be appended to something else.
- A software extension or hardware peripheral that provides additional functions or customization for a core application or system.
- Additional chips that can be purchased at specific times in tournament play.