Be prepared to pay more than, having a lot to gain

I think it could be either:

Which length description are you looking for?:

3,7

10*

bid against

I'm a little stuck... Click here to teach me more about this clue!

'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.

Can you help me to learn more?

I've seen this clue in the Evening Standard.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.