Since we're assuming predeterminism here, I'll take 2 million dollars please. I can always take comfort in the fact that I couldn't possibly have made any other choice.
The problem is that I don't believe in predeterminism and that means that I don't believe that you could possibly know when I'm going to die. So I might be inclined to call your bluff so to speak and make a deal for 50 million.
Having said that however, if I found myself sitting inside a surreptitious looking limousine looking across at you dressed in your high-priced suit and noticed that unmistakably evil yet charismatic twinkle in your eye as you waited with baited breath for me to put pen to paper, I'd be outta there in a flash. You can keep your damned money. In the end I'm not certain enough about anything to take the risk.
Then again, maybe you're just someone who is very rich and very bored who has finally found something amusing to do.