Viña [1]’s Hostelling International affiliate is Hotel Asturias (Av. Valparaíso 299, tel. 0322/711565, hivinaasturias [at] hostelling [dot] cl, US$11–12 pp).
In summer, when it gets crowded, the overflow goes to Hotel Capric (Von Schroeders 39, tel. 0322/978295, hivina capric [at] hostelling [dot] cl, US$11–12 pp).
Links:
[1] http://www.moon.com/destinations/chile/-chilean-heartland/vina-del-mar