It is an "entry level" Triple Triangle frame. GT has made numerous bikes ,Avalanche, Backwoods...etc with this frame. I will be VERY general here and say that it is a perfectly good frame for basic mountain biking.
There were and are still different levels of the Avalanche, (last time I looked, not recently). This bike was most likely in the neighborhood of $300 to $600. This is not to be taken as gospel as I have not looked at GT much. I recieved an early 90s GT bike (backwoods) a while back and briefly investigated what I had. The Triple Triangle frame has a few fans over at MB review.com, or whatever that site is.