Nobody seems to be saying how much the new, or used, F-18s will cost, but a new Euro Typhoon only costs about $150M U.S.
The Typhoon out performs the F-18, and is at about par with F-35, and at a price that is probably about half the price of a used F-18, it seems like a no-brainer to buy new Typhoons.
As others have pointed out, the used submarine mess should be enough to put the decision over the top.
As an added bonus, buying Typhoons would be a snub of Boeing.