Cheap old whiskey drunk by Grant (3-3)
I believe the answer is:
low-end
'grant' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'cheap old whiskey drunk by' is the wordplay.
'cheap' becomes 'low'.
'old whiskey drunk' becomes 'end' (I can't explain this - if you can you should give a lot more credence to this answer).
'by' says to put letters next to each other.
'low'+'end'='LOW-END'
Can you help me to learn more?
(Another definition for low-end that I've seen is " budget".)