Here is a list from least expensive and exclusive to most (as far as I understand it).
Glenmorangie Standard 10 Year - $30-35
Glenmorangie 12 Quinta Ruban - $40-60
" Lasanta - $40-60
" Nector d'Or - $40-60
" Astar -$70-90
" Ealanta - $70-90
Glenmorangie 18 Extremely Rare - $70-80
Glenmorangie Finealta (peated) - $~100
Glenmorangie Signet - $140-200
Glenmorangie 25 Year - $~300-600
Glenmorangie Truffle Oak - $~1500
Glenmorangie Sauternes 1981 - $2000-3000
Glenmorangie Special Release Vintages (old stuff) - $$$A lot.
These are just what I know of, I'm sure there are more. The 12 year range is just a bunch of whiskies aged in different kinds of barrels for different effects, for 12 years each.
The Signet doesn't have an age as far as I know, but it is distilled from heavily malted barley called "chocolate malt." This creates a deeply and richly unique flavor effect.
Here is a link with tasting notes and info: