I think an entrepreneur who can't scrap up $500 for lunch if they believed it would help them succeed is unlikely to be much of a success. You must have some marketable skill and ability to make money with that skill....
That's not to say if if your idea is freaking amazing or you two click, he isn't ABLE to fund you. The chance is slim, but maybe just slightly more then meeting him on the street since he'll listen to what you have to say since your money is going to a good cause.
Either way, bid. The chance to meet him alone is worth $500 in my book.