It depends on the size and type of extension. Small porches or flat roof extensions are very reasonably priced. More substantial two storey extensions can be expensive. In general, the price is roughly proportional to the amount of space you add to your home.
Berriedale
Berriedale is a tiny estate village on the northern east coastline of Caithness, Scotland, on the A9 road between Helmsdale as well as Lybster, close to the border between Caithness as well as Sutherland. It is sheltered from the North Sea. The village has a parish church in the Church of Scotland. Just southern of Berriedale, on the way to the north, the A9 passes the Berriedale Braes, a steep drop in the landscape (brae is a Scots word for hillside, a borrowing of the Scottish Gaelic bràighe). The roadway drops down outstanding (13% over 1,3 kilometres) to bridge a river, before climbing once more (13% over 1,3 kilometres), with a number of sharp bends in the road-- although several of the hairpin flexes as well as various other neighboring slopes have actually been relieved in the last few years. The impracticality (as well as expense) of linking the Berriedale Braes stopped the building of the Inverness-Wick Far North Line along the eastern coastline of Caithness; rather the train runs inland via the Flow Country. Berriedale lies at the end of the 8th stage of the seaside John o' Groats Route.