This is one of the many caveats to the cloud, honestly. I really am a cloud advocate. I think the public / private cloud solves a ton of issues that we had in a pre-cloud world, but I also think it created a bunch of other just-as-bad problems.
The pricing structure for cloud instances is supposed to be and has always promised to be much cheaper and easier to understand than physical devices. This, 99.9% of the time is never true. I always feel nickel-and-dimed to death whenever I leverage the cloud. It truly makes me sad. The cloud already has a bad wrap, so why do we insist on killing it again? Doesn't quite make sense to me.