Blank book in sale with no covers, worthless (5)
I believe the answer is:
album
'blank book' is the definition.
(I've seen this before)
'sale with no covers worthless' is the wordplay.
I cannot quite see how this works, but
'worthless' could be 'bum' (bum can mean of poor quality) and 'bum' is found in the answer.
The remaining letters 'al' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'in' acts as a link.
Can you help me to learn more?
(Other definitions for album that I've seen before include "LP, CD; blank book" , "Book for stamps/photos" , "Music record or photo book" , "Compilation of recordings" , "CD, say" .)