Telescopes, initially scarce, procured? Yes - getting used by girls (10)
I believe the answer is:
spyglasses
'telescopes' is the definition.
(spyglass is a kind of telescope)
'initially scarce procured? yes getting used by girls' is the wordplay.
'initially' suggests taking the first letters.
'used by' means one lot of letters go next to another.
'girls' becomes 'lasses' (lass is a kind of girl**).
The first letters of 'scarce procured yes getting' is 'spyg'.
'spyg'+'lasses'='SPYGLASSES'
(Other definitions for spyglasses that I've seen before include "good lookers?" , "Telescopes" .)