Fierce sort of row about £1,000 (5)

I believe the answer is:

tiger

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'fierce sort' is the definition.
(a fierce animal)

'row about ps1000' is the wordplay.
'row' becomes 'tier' (tier is a kind of row).
'about' is an insertion indicator.
'psg000' becomes 'g' (I can't explain this - if you can you should give a lot more credence to this answer).
'tier' placed around 'g' is 'TIGER'.

'of' acts as a link.

Can you help me to learn more?

(Other definitions for tiger that I've seen before include "Dynamic type - striped animal" , "Dangerous animal" , "Striped feline" , "Large forest cat" , "Dynamo" .)

I've seen this clue in The Guardian.

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