At least for anyone paying in USD, 1 Crysta = 1 penny, both when buying them and when spending them to get subscription time. (I'm not quite sure how the Euro equivalent works out.)
180 days costs $77.94 or 7794 Crysta.

I'm not sure what that 186 Crysta cost is about. I think that page must be screwed up somehow. It's already suspicious that it says in one case that your sub is still valid but doesn't say the same in the other case.