How you said "I paid a thousand dollars for it"? (7)

I believe the answer is:

grandly

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'how you said i paid a' is the definition.
I can't judge whether this defines the answer.

'thousand dollars for it?' is the wordplay.
'thousand dollars' becomes 'grand' (I've seen this in another clue).
'for it?' becomes 'ly' (I can't justify this - if you can you should give a lot more credence to this answer).
'grand'+'ly'='GRANDLY'

Can you help me to learn more?

I've seen this clue in the Evening Standard.

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