I'm going to be buying a RT ticket on LAN from LIM-CUZ for March and I see that a number of fare classes are available (see link below). The cheapest fare class has the following restrictions/terms:

Other conditions
The ticket is valid for 6 month from the issue date
The fare allow LanPass kilometers accrual
The fare DOES NOT allow LanPass upgrade certificates
The fare DOES NOT allow seat reservation
The fare DOES NOT allow pre checkin

Does the no seat reservation condition mean that I would essentially be flying standby, or simply that I cannot select a specific seat in advance? I want to definitely be on the specific flight that I am booking since I'm meeting a friend in Cuzco who is coming down from LA and I don't want to get to the airport to find that I have no seat on the plane because I was trying to save $20.

Also - does anyone know if it is cheaper to book this with a local agent once I get to Lima instead of in advance online so I can shoot for student discount/etc.? Thank you!!!

Here's the link:
http://tinyurl.com/4w8av

peace,
~Ben~