for others looking for cuzco tickets...
the $212 fare for taca peru is C class. you can get the $171 Y class fare on expedia by checking the unrestricted button, but leaving the advance purchase button unchecked. and you get a fare of $171, which should be Y, but you can't really tell on expedia. on travelocity and itn, i couldn't get the $171, to come up. only the $212 business class fare. at any rate it is a lot to pay since you can get tickets much cheaper locally in peru.