They got an excellent deal on them as there is no commercial market for ex-military tankers - apart from companies that want to use them as tankers !
Civilian passenger / cargo companies want newer models with low operating cost and as much commonality as possible with their existing fleet - and therefore would not be interested - and that was reflected in the price. A bargain compared to $200M+ for a new A330 MRTT.
Omega probably didn't have the cash to pay for them - they are not a publicly traded company and so couldn't use shares - even if they were smart enough to think of doing that. ---------------------------------------------------------------------- There is of course nothing wrong with the Tristars as I have previously explained here: