// Method called from UI button to buy units of a Ship.
public void Buy()
{
if (currencyManager.currency >= cost * quantityMultiplier)
{
currencyManager.currency -= cost;
quantity += quantityMultiplier;
currencyManager.ChangeCurrencyIdleGain(currencyGain * quantityMultiplier);
UpdateValues();
if (quantity >= shipData.qtToUnlockNextShip)
{
UnlockNextShip();
}
// Play sound.
}
else
{
// Play different sound.
}
}