It is costing nothing to woo? Yes perhaps (8)
I believe the answer is:
courtesy
'it is costing nothing' is the definition.
The definition suggests a singular noun which matches the answer.
'woo? yes perhaps' is the wordplay.
'woo?' becomes 'court' ('court' can be a synonym of 'woo').
'perhaps' indicates an anagram.
'yes' with letters rearranged gives 'esy'.
'court'+'esy'='COURTESY'
'to' is the link.
Can you help me to learn more?
(Other definitions for courtesy that I've seen before include "Respectful and considerate behaviour" , "Polite behaviour" , "Politeness and respect for others" , "good breeding" , "Civility, politeness" .)