Number with purpose getting a great deal (2,3)
I believe the answer is:
no end
'a great deal' is the definition.
(thesaurus)
'number with purpose' is the wordplay.
'number' becomes 'no' (abbreviation for 'number').
'with' is a charade indicator (letters next to each other).
'purpose' becomes 'end' (I've seen this before**).
'no'+'end'='NO END'
'getting' is the link.
(Other definitions for no end that I've seen before include "Without limit" , "goalless?" , "Very much (slang)" , "Non-stop" , "what eternity offers?" .)