It's not for nothing you pass through it (4,4)
I believe the answer is:
toll gate
'it's not' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'for nothing you pass through it' is the wordplay.
I cannot really see how this works, but
'for' could be 'to' (eg both can mean 'in the opinion of') and 'to' is located in the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is present in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for toll gate that I've seen is " where traffic never passes freely?".)