Disorganised, Sally saving time at the end (6)
I believe the answer is:
lastly
'at the end' is the definition.
(I've seen this before)
'disorganised sally saving time' is the wordplay.
'disorganised' is an anagram indicator.
'saving' indicates putting letters inside.
'time' becomes 't' (abbreviation).
'sally' anagrammed gives 'lasly'.
'lasly' placed around 't' is 'LASTLY'.
(Other definitions for lastly that I've seen before include "In the end" , "In conclusion" , "Finally, to conclude with" .)