Stops by, though a toll is exacted from? (4,1,5)

'stops by' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.

'a toll is exacted from?' is the wordplay.
I cannot quite understand how this works, but
'a' is within the answer.
'is' is present in the answer.
This explanation may well be incorrect...

'though' acts as a link.

Can you help me to learn more?