Remember you get 1 Farm Town Cash for each level you reach. Some things in Farm Town can only be bought with Farm Cash.
According to the Official Farm Town Slashkey forums:
Each time you level-up in the game you will be awarded with 1FC for free. This means if you have never spent FarmCash and you are at level 33 of the game, you will have at least 33FC on the game.
You can see your FC by looking at the counter which is right under your coins counter.