There's no duty here and no charge for wine (4,4)

I believe the answer is:

free port

I'm a little stuck... Click here to teach me more about this clue!

'there's no duty here' is the definition.
The answer is a location as well as being a singular noun. This is suggested by the definition.

'no charge for wine' is the wordplay.
'no charge' becomes 'free' (synonyms).
'for' says to put letters next to each other.
'wine' becomes 'port' (port wine is a kind of wine).
'free'+'port'='FREE PORT'

'and' acts as a link.

Can you help me to learn more?

(Another definition for free port that I've seen is " Haven open to all traders".)

I've seen this clue in The Globe and Mail.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.