free - I have two Phillip's 20's ... Grace just got set up for commuting and utilitarian riding and at some point I plan to add a hitch for my trailer since she has the gearing for it and if she doesn't, I have bigger cogs.
One issue I found with my larger paniers is that with the short stays on the Twenty kicking them was a problem... running smaller paniers in the rear and the same up front might address this.