A cent — price for buttonhole? (6)
I believe the answer is:
accost
'buttonhole?' is the definition.
(both can mean to detain in conversation)
'a cent price' is the wordplay.
'cent' becomes 'c'.
'price' becomes 'cost' (synonyms).
'a'+'c'+'cost'='ACCOST'
'for' acts as a link.
(Other definitions for accost that I've seen before include "approach with menaces" , "Tackle" , "Stop and pester" , "Buttonhole" , "Meet and greet" .)