The 18 (18 years in the cask before bottling) is going for around $150 per 750 ml bottle now. It's the finest single malt, all around, that I've ever come across. Pass a dram down the table, without anyone drinking it, just smelling it as it passes, then ask the folks at the table what they think. Oh for gosh sake. Those spending $150 for the stuff have more money than sense.
The 12 year is selling for under $50. I tasted them side by side. The 18 year is nicer, but anyone who thinks the 18 year is 3 times better deserves to be parted from his money, but doesn't deserve good scotch. Slip him something else. A fool of his caliber won't know the difference.
I don't buy either the 12 or the 18. However, when I'm on a vendor's dime I tend to get a shot of the 18. When I'm on my own I get the Famous Grouse blend (g).