Which of these two is the correct form to say?
I would sell my book if you give me 100 dollars
or
I would sell my book if you pay me 100 dollars
Are there alternatives to say the same?
Both of these sentences are acceptable, with the latter being more natural. This is because you directly can associate 'pay' with 'sell' or 'buy'.
Additionally, you can even say:
I would sell my book to you for 100 dollars