£1000 getting a lot of rubbish wine (5,3)
I believe the answer is:
grand cru
'wine' is the definition.
(term for high-quality wine)
'ps1000 getting a lot of rubbish' is the wordplay.
'psg000' becomes 'grand' (I am not sure about this - if you are sure you should believe this answer much more).
'getting' says to put letters next to each other.
'a lot of' means to remove the last letter (I've seen 'lots of' mean this (the majority of the word)).
'rubbish' becomes 'crud' (both can mean nonsense).
'crud' with its last letter taken away is 'cru'.
'grand'+'cru'='GRAND CRU'
(Other definitions for grand cru that I've seen before include "Superior wine" , "special wine" , "Type of wine" , "A wine of the best grade" , "fine wine" .)