While I agree the prices for bag/vault space is high, also (and this has been talked about in so many other threads) the Zen prices are high in general. IF you decide to spend real money. I think what causes the Zen prices to be so high is the Zen to AD trading. With that market you never need spend a single penny on this…
And one other thing. You cannot complete skirmishes that are below your level as the only way to get to them is through the queue system. You can still go in and do dungeons by going to the door in the zone, just can't queue for them (at least if you are less than level 60) Hope that helps.