Note stair gets fixed for nothing (6)
I believe the answer is:
gratis
'nothing' is the definition.
(I've seen this before)
'note stair gets fixed' is the wordplay.
I cannot quite understand how this works, but
'note' could be 'ti' (I've seen this in other clues) and 'ti' is found within the answer.
This may be the basis of clue (or it may be nonsense).
'for' acts as a link.
Can you help me to learn more?
(Other definitions for gratis that I've seen before include "Free (Latin)" , "Free, costs nothing" , "not charged" , "Without charge" , "Without payment" .)