They may subsidise part of service, but only with one rupee (6)

'they may subsidise' is the definition.
(people who pay for others)

'part of service but only with one rupee' is the wordplay.
I cannot really understand how this works, but
'one' could be 'a' (a thing is one thing) and 'a' is located in the answer.
'rupee' could be 'r' and 'r' is found within the answer.
The remaining letters 'pyes' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...