The prices have increased recently and there’s some confusion about what’s now covered as MSC is currently making changes but they haven’t yet been implemented across the fleet. There are a couple of threads around this that you should read. Then it’ll be clear as mud to you (we’re talking about MSC here, after all).
The Easy package is €39, EasyPlus is €54 and PremiumExtra is €74. They’re the prices you’ll be charged onboard when the onboard currency is €, plus the service charge (which used to be 15% but that’s been increased to 18%). I don’t have the new $ prices. As @insidecabin has said, you may get a promotional rate when making a booking.
MSC does not indicate a price limit for the Easy package; they have a menu onboard listing the inclusions. For the other two, you will be covered for drinks up to €9 and €14, respectively (but that’s not the situation at the moment. From some reports on here, the old limits seem to still be in place).
The previous prices for the packages in $ were: $38, $49 and $69, respectively. These have now increased, as have the drinks price limits which I include in brackets here. The 2 higher packages covered drinks up to $9 (now $10) and $15 (now $16).