Show on offer (9)
I believe the answer is:
represent
'show' is the definition.
(I've seen this before)
'on offer' is the wordplay.
'on' becomes 're' ('on' can be mean 'with reference to').
'offer' becomes 'present' (I've seen this in another clue).
're'+'present'='REPRESENT'
(Other definitions for represent that I've seen before include "Portray" , "Serve as a symbol for" , "Illustrate" , "show" , "Picture" .)