There's a bad side to the story. The horses didn't went trough not because of tax but because the administration wasn't done properly.
When people realized there was only a limited amount of horses, people just started bidding - 530 is a confirmed price, but I heard rumors of 800 euros.
Btw, Kitty, I was indeed in a French regiment, but I left that a month ago. I'm now only a member of my cavalry group, and I joined the Landwehr group for just this event, although I might be joining them.