A typical street in MendozaThere are several possible buses that make the daily run from Valparaiso, Chile (originating in Vina del Mar) to Mendoza and they cost about CLP9000/$19 for the 15 hour bus ride. I suggest either Tas-Choapa or El Rapido as they both offer good service, reasonable price, and safe buses.
Crossing the Chile-Argentina border was a breeze; just make sure to eat all your fruit before you get there.
Valparaiso, ChileThe buses leave from Santiago for Valparaiso every 10-15 minutes from Terminal Alameda. TurBus seems to be the cheapest option at CLP3200/$6.60. The trip only took about an hour and a half. In Valparaiso, we stayed at Casa Valparaiso Hostel, which cost us CLP9000/$18.60 for a private double with shared bathroom, kitchen, internet, cable TV, and extras!
View of Santiago from Cerro San Cristobal.We took TurBus from La Serena to Santiago. The trip was about five hours and cost CLP8000/$17. It was amazing how similar Santiago seemed to Toronto on the drive in on the highway through the outskirts. We had read some negative things about Santiago, particularly about the pollution problem. Unfortunately, in the winter months a thick layer of smog drapes the city creating scenes like this.