It really all depends on where in the world your are, specially since very few shops in Europe ships to the US or Canada.
As for whiskies from 1977:
* The Whisky Exchange
has a t least 20 different bottling, with prices ranging from £45 (Banff, OMC). (Press search / Enter vintage)
* Loch Fyne Whiskies
also have some, with a Rare Malts Bladnoch 1977 as the cheapest I could find in a hurry for £63.90
* Royal Mile Whiskies
also has one or two. With prices starting at £42.50 (Signatory Ardmore)
Leaving Britain we have:
in Basel (Switzerland) - I found eight 1977 single malts (prices from CHF 178).
* At Weinquelle
in Germany I found just three, with prices from €67.50
* In the US The Whisky Shop USA
has at least seven different bottling, raning from US$135