Volunteers a kiss as payment! (3)
I believe the answer is:
tax
'payment' is the definition.
The definition and answer can be both related to property as well as being singular nouns.
Maybe you can see a link between them that I don't see?
'volunteers a kiss' is the wordplay.
'volunteers' becomes 'ta' (abbreviation for Territorial Army).
'a kiss' becomes 'x'.
'ta'+'x'='TAX'
'as' is the link.
Can you help me to learn more?
(Other definitions for tax that I've seen before include "E.g. VAT" , "Government imposition" , "Levy for public purposes" , "Overburden with levy?" , "Compulsory contribution towards a country's expenses" .)