Unpleasant girl starts cheap comic (5-8)
I believe the answer is:
penny-dreadful
'starts cheap comic' is the definition.
I don't know anything about this answer so I can't judge whether this works.
'unpleasant girl' is the wordplay.
I cannot really understand how this works, but
'unpleasant' could be 'dreadful' (similar in meaning) and 'dreadful' is found within the answer.
'girl' could be 'pen' and 'pen' is found within the answer.
The remaining letters 'ny' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for penny-dreadful that I've seen before include "Melodramatic paperback novel" , "Cheap, sensational serial or book" , "Cheap and sensational novel" , "Junior relation of the shilling shocker?" , "Cheap storybook" .)