Complete a tower defense level without losing any lives to get a Bloonstone reward. Bloonstones are the game's premium currency and are used to complete construction faster and continuing a level after all your lives have been depleted.
Coins
The amount of coins your city can hold is limited by the number of monkey banks that were constructed. The single bank you begin with is capped at 1,500 coins. Make sure to spend coins before hitting your limit.
Expanding
When first starting, you will have to claim more land to expand your city. To this, win tower defense levels. You can now build anything desired on the new land. Tap an unclaimed land space, and a Bloons icon and several dots will appear. The amount of dots that are highlighted indicate how difficult the stage will be considering your current equipment. When first starting, only play levels that are rated at two dots.