I'm a trader that's perfect (5)
I believe the answer is:
ideal
'perfect' is the definition.
(similar in meaning)
'i'm a trader' is the wordplay.
'i'm' becomes 'i' (I've seen this in other clues).
'a trader' becomes 'deal' (I can't explain this - if you can you should give a lot more credence to this answer).
'i'+'deal'='IDEAL'
'that's' acts as a link.
Can you help me to learn more?
(Other definitions for ideal that I've seen before include "An - - Husband (Wilde)" , "Paradigm" , "Model of perfection" , "example" , "To which one aspires" .)