The price of the bundle depends on the contents of the bundle. As an estimate, probably 50% of the total value of games in the bundle.
I've seen some bundles run for just a single week, only for the submitters to not accept it in time. This bundle will only have 5 creators, so that shouldn't be much of a problem. I think the bundle shall run for about 2-4 weeks, to give space to accept it.