public void Upgrade()
{
if (currTier < tierCost.Length - 1)
{
int totalCurrency = scoreKeeper.GetTotalCurrency();
if (totalCurrency >= tierCost[currTier + 1])
{
scoreKeeper.AddCurrency(-1 * tierCost[currTier + 1]);
IncTier();
Debug.Log("UPGRADED!");
}
}
}