I realised that most money in this game is used for wars, so I figured I can save the most money if I do not participate in those wars. However, if I do not participate in those wars, my side may lose.
I thought, why not talk to someone else who also wants his side to win but does not want to waste money.
The idea: You look for an enemy with the same damage potential and both agree to not participate in the battle. No damage disadvantage for your side, since the enemy also does not have that same damage for themselves. You both save money. Win, win.
You guys may use this article's comment section to find someone your level and make an agreement to not attack in order to save money.