Here are some ways that you can earn coins and gems without having to spend money.
1.) Collect your daily rewards everyday. Click on the ad option to get double the reward.
2.) Watch the gems ad daily to get 2 free gems.
3.) Play arena mode and get 12 wins. You can earn good gems in the chest. Play many runs a day to accumulate gems.
4.) Keep playing quick play to get coin chests. The normal coin chests gives about 50+ coins. The ad coin chests give over 200 coins.
5.) Complete your daily quests. These quests give coins and exp points.
6.) Get Challenger/Gladiator/Champion Rank in Arena mode by earning arena ratings in each Arena season. Reaching these tiers will give you exp and some coins.
7.) Join a clan and collect the clan spin every Monday. You can get exp, coins and possibly a clan reward item.
8.) Participate in #FunRunFriday event every Friday on Fun Run’s official social media pages.