Bill's on cover but nothing inside newspaper (7)
I believe the answer is:
tabloid
'newspaper' is the definition.
(I know that Tabloid is a type of newspaper)
'bill's on cover but nothing' is the wordplay.
I cannot quite see how this works, but
'nothing' could be 'o' (O resembles 0) and 'o' is found within the answer.
'cover' could be 'lid' (lid is a kind of cover) and 'lid' is located in the remaining letters.
'bill' could be 'tab' (a tab is a bill at a bar) and 'tab' is found in the answer.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
'inside' is the link.
(Other definitions for tabloid that I've seen before include "Cheap newspaper" , "Small format newspaper" , "Newspaper with smaller pages and popular content" , "Type of newspaper" , "Populist newspaper" .)