I don't think that everyone would be willing to pay for that amount if somebody goes $100k first. But that's a good challenge for everyone. I don't think the prize is necessary.
Unless you make this as an official contest with prize escrowed.
Not many people would be interested in this. To me it looks like something extra, and these days doing the extra on here rather than with family just isn't for me. There is also no real incentive to doing this contest and it just doesn't come across serious either...