on right click:
	if target block is a sign:
		if line 1 is "[COMPRAR]":
			if line 2 is set:
				set {_comprarregion.%player%} to line 2
				set {_comprarpreco.%player%} to line 3
				if player's balance is {_comprarpreco.%player%}:
					remove {_comprarpreco.%player%} from player's balance