One in Red Sea resort needs cash (7)
I believe the answer is:
readies
'cash' is the definition.
(I've seen this before)
'one in red sea resort' is the wordplay.
'one' becomes 'i' (Roman numeral).
'in' indicates putting letters inside.
'resort' indicates an anagram.
'red'+'sea'='redsea'
'redsea' is an anagram of 'reades'.
'i' going into 'reades' is 'READIES'.
'needs' acts as a link.
(Other definitions for readies that I've seen before include "Cash -- a desire (anag)" , "Bank notes" , "The - - : cash (sl.)" , "money" .)