After some days are over, I have to say that the gold costs are strange. I don't feel comfortable with it. You can buy a limitless amount of ammunition for always the same price. When the prices would increase each time you buy it I would feel more comfortable with it.But when it's coming to buying more ammunition, the prices for these are rediculous. 10 ammunition is exactly one shot and 1/10 of the ammunition you can get per day. and this one single shot costs 150 gold. This seems to be a very high price for it.
My first thought on this was that 150 gold is a lot for one additional shot. But there are many many rewards in this event (too many to be honest) and the fact, that the prices don't increase at all it is really low for powergolders but a high price for occasional gold users. Personally, I prefer the increasing system.