This month, material of mine is available to buy (2,5)
I believe the answer is:
in store
'mine is available to buy' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'this month material' is the wordplay.
'this month' becomes 'inst' (letter-writing abbreviation for this month).
'material' becomes 'ore' (ore is a kind of material).
'inst'+'ore'='IN-STORE'
'of' is the link.
Can you help me to learn more?
(Other definitions for in store that I've seen before include "at the supermarket" , "Approaching" , "coming soon" , "Awaiting delivery" , "Sort of bakery" .)