I am hunger for free gems in Clash of Clans. Yes, you can get most of the free gems in Achievements. Friend in Need has 280 gems in total to get. However, fulfilling 25000 Clan Castle capacity worth of reinforcements is not easy. And will take a long time to complete. No worry, there is a super fast and easy way to get those free gems.
Yes, be a hopper from clan to clan. Make sure that you have enough elixir. Then you need to leave current clan for a while. Join any clan randomly. And donate reinforcement troops for those needed in that clan. Look for green arrow (up or down). No arrow == no more troop request. Leave that clan then. Join another one later. Then repeat the same thing… The best and economy way is to donate Barbarian which is the cheapest and fastest to train. Giant is the fastest way to fulfil all troop request but expensive.
Well, that’s it. Enjoy free Clash of Clans gems. I am going to get my 4th builder soon.