Time and cost would depend on the method of transportation used ie guagua, taxi or motoconcho.
Be advised...the taxis within the Costambar complex are a huge rip off...never did use them. If your amigo knows of a "non-tourist" taxi, go with that option. (they will just need to hide their signs entering the complex).
Time from the main gate is approximately 15mins depending on whose behind the wheel

.