Item of crop initially sold on eBay, controversially (3,4)
I believe the answer is:
soy bean
'item of crop initially sold' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'on ebay controversially' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'ebay' is 'ybea' which is located in the answer.
'on' is present in the answer.
A single letter 's' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Another definition for soy bean that I've seen is " Source of oil".)