If you are lacking coins in Frontierville then there is a neat way for you to gain a few extra coins. You will first need a 1000 coins to get this trick started.
Plant the cheapest crop available. Usually a clover (price may change).
#2 Step Two
Wait for the crop to wither.
#3 Step Three
Clear the withered crop.
#4 Step Four
Collect the coins. For example, if you buy two clovers then you will get a 6 coins profit for every two crops. You also do not lose any energy as you do not need energy to harvest or get rid of withered crops. But make sure to collect your coins soon before they disappear.