Mistake wearing jewel that’s cheap? (8)

I believe the answer is:

rubbishy

'cheap?' is the definition.
(thesaurus)

'mistake wearing jewel' is the wordplay.
'mistake' becomes 'bish' (I've seen this in other clues).
'wearing' is an insertion indicator.
'jewel' becomes 'ruby' (ruby is a kind of jewel).
'bish' inserted into 'ruby' is 'RUBBISHY'.

'that's' acts as a link.

(Another definition for rubbishy that I've seen is " Poor-quality".)

I've seen this clue in The Times.

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