Sort of service for 51p? (3)
I believe the answer is:
lip
'sort of service' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Perhaps you can see a link between them that I can't see?
'for 51p?' is the wordplay.
'for' becomes 'li' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'li'+'p'='LIP'
Can you help me to learn more?
(Other definitions for lip that I've seen before include "Fleshy fold of mouth tissue" , "giving such insincere service" , "Edge of mouth" , "Sauce" , "In slang, impudent talk" .)