Be prepared to pay more than, having a lot to gain (3,7)

I think it could be either:

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3,7

10*

bid against

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'be prepared to pay more than' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.

'a lot to gain' is the wordplay.
I cannot quite see how this works, but
'a' is within the answer.
'lot' could be 'd' and 'd' is found within the answer.
'to gain' could be 'gain' and 'gain' is found in the answer.
This may be the basis of clue (or it may be nonsense).

'having' is the link.

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I've seen this clue in the Evening Standard.

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