Attract expensive space first (6)
I believe the answer is:
endear
'attract' is the definition.
(I've seen this before)
'expensive space first' is the wordplay.
'expensive' becomes 'dear' (similar in meaning).
'space' becomes 'en' (in printing, a space as wide as a letter 'n').
'first' says to put letters next to each other.
'dear' put after 'en' is 'ENDEAR'.
(Other definitions for endear that I've seen before include "Earned (anag.)" , "Neared in order to charm" , "Give popularity to" , "Make lovable or please" , "Win over" .)