I give you an example.
We are doing the Transatlantic cruise with the Splendour, starting november 12th in Barcelona, ending november 26 th in Houston.
We are paying for an inside stateroom on deck 7, categorie K, including airfare Dusseldorf(Germany)-Barcelona(Spain)and back Houston to Dusseldorf 1.138 Euro, thats about 910 US $.
Our friends have a special offer for this cruise in a balkony cabin also on deck 7 for 1.349 Euro, about 1.080 US $.
And yes, the repositioning cruises are much cheaper in their price than other cruises.
I have compared the prices with internet cruise specialist in the US and the price they ask is almost the same, but without the flights.