Coin Strategy - ATM
The strategy I am about to explain here is called ATM strategy, it is an easy way to get coins without having dwellings.
The concept is this, you need to attack 200 Level 1 RBC and then all the RBCs stop leveling up. So, then you can attack RBC in Ice or Sand or Fire and they wont level up. So you can attack 9 RBCs everyday and collect a lot of coins. As all of them would be at the same level, so you need to spy only 1 of them and all the rest would have the same number and formation of soldiers and tools.