I bought for 36.000 gold 160 Santa's gift containers and got this:
30 day prem: 1 times
50 Flag: 50 times (economic flags, but no -10% post battle)
300 gold: 17 times
4-5 Camo: 62 times
10.000 XP: 21 times
2500 Coal: 8 times
Ship:
Genova (lvl 5) + captain (lvl 10).
Afterwards I bought for 22.500 gold 20 Santa's Mega gift containers:
150 flags (special flags)
2000 gold
135 camo
37500 coal
Ships:
Vanguard (lvl 8) + captain (lvl10)
Yahagi (lvl 5) + captain (lvl10)
Benham (lvl 9) + captain (lvl10)
P. Bagration (lvl 8) + captain (lvl10)
Before buying containers I had 74 gold/special ships ranging from lvl 2-10
In this particular case Mega containers was better for me than the normal containers since I prefer ships over any other resources.