Boom Beach: Here’s Every Known Method of Getting Free Diamonds (and other resources).

WP – "Boom Beach might be a very different game from Clash of Clans (seriously, it is – don't be fooled by the look), but there are some VERY notable similarities – mainly that if you have a credit card in good standing, and you get bit by the IAP bug, you can say goodbye to said good standing (and to your kid's college fund). Thankfully, the kind souls over at Supercell Oy haven't left their fans COMPLETELY high and dry. Just mostly (fine, I kid, I kid). Oh, and gold, wood, stone and iron are also important."