Meal reduced by 1p. Great! (5)
I believe the answer is:
super
'great' is the definition.
(I've seen this before)
'meal reduced by 1p' is the wordplay.
I cannot really understand how this works, but
'by' could be 'per' (I've seen this in another clue) and 'per' is found in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for super that I've seen before include "Prefix meaning over-excellent!" , "Prefix meaning above or informally great" , "Terrific, ace" , "Informally great, really up there" , "Delightful" .)