Cava and fuel unfortunately take on English list price (4,5)
I believe the answer is:
face value
'list price' is the definition.
'face value' can be an answer for 'price' (thesaurus). I am not sure about the 'list' bit.
'cava and fuel unfortunately take on english' is the wordplay.
'and' is a charade indicator (letters next to each other).
'unfortunately' indicates an anagram (a bad or unfortunate spelling).
'take on' is a charade indicator (letters next to each other).
'english' becomes 'E' (abbreviation).
'cava' after 'fuel' is 'fuelcava'.
'fuelcava' is an anagram of 'facevalu'.
'facevalu'+'e'='FACE VALUE'
Can you help me to learn more?
(Other definitions for face value that I've seen before include "not an excessive price" , "For Helen, a thousand ships" , "Apparent worth" , "Amount as printed or stamped on money or other object" , "really not worth it?" .)