I purchased a ticket on Sky airlines out of Chile. The BA/Santiago trip took an hour and cost all of $29!! Check out Sky on the Chilean site; it has some really good prices. The trip from Mendoza/Santiago on the bus is beautiful, granted, but from BA to MDZA is always overnight. SENDAS is a good bus to take and comfortable cama suite but it's expensive, of course, and $29 is still much cheaper! Do you have a DNI? Flying to Mendoza by buying the ticket is advance is cheaper than a coche/cama bus trip, and then taking the bus across the mountain for the scenery aspect is another option. I've done all of the above and I've gone about ten times so my favorite option is flying for $29.