The Idler and the Devil

An idler sighed, 'Everyone says, 'We don't need idlers. You are always in the way. Go to the devil!' But will the devil tell me to get rich?'
No sooner did the idler say this than the devil himself stood in front of him.
'Well', said the devil, 'the work I have for you is light, and you will get rich. Do you see the bridge? Just walk across and I will double the money you have now. In fact, each time you cross I will double your money.'
'You don't say!'
'But there is one small thing. Since I am so generous you must give me $24 after each crossing.'
The idler agreed. He crossed the bridge, stopped to count his money ... a miracle! It had doubled.
He threw $24 to the devil and crossed again. His money doubled, he paid another $24, crossed a third time. Again his money doubled. But now he had only $24, and he had to give it all to the devil. The devil laughed and vanished.
The moral: When anyone gives you advice, you should think before you act.
How much money did the idler start with?