I have noted that prices seem reasonable.. but are jacked up if you want a cabin with an external window or balcony.
I have never been on a cruise so can't really offer anything helpful, but my immediate reaction to this is sheer horror at the idea of a cabin without external windows. Sounds to me like the perfect conditions to induce seasickness. That said, I never suffer from seasickness - I famously once slept like a log through a very rough overnight channel crossing while the rest of my family were up all night chundering.
ETA: also, I could be talking complete rubbish - a quick google suggests more people have problems with seasickness with exterior cabins, which surprises me, but what do I know?
Somehow it seems like an industry calculated to get you interested in a low intial price then have plenty of add-ons.
Often the corollary to "prices seem reasonable" (see also: easyJet)
