Six Day prize money

I was reading something about one of the six day races and saw a reference to big prize money, so searched around out of curiosity and couldn't find anything about what kind of prize money is on offer for six day races. Does anyone have any ideas?
As a rule, prize money in Sixes is of lesser importance than the appearance fees paid to the riders, which are usually scaled to the pulling power of each rider. Most organisers are of the view that paying riders and letting them put on a show is a better approach than making them duke it out for prize money, which can result in boring racing. Sadly, like criteriums, organisers tend not to talk publicly about their finances, even as they brag that they're offering serious prize money.