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.
Bala
Bala is a market community and also area in Gwynedd, Wales. Previously a city district, Bala exists within the historical county of Merionethshire. It lies at the north end of Llyn Tegid, 17 miles (27 km) north-east of Dolgellau, with a population taken in the United Kingdom Census 2011 of 1,974. It is little more than one broad street, this being Stryd Fawr (High Street, literally "Great Street"). The High Street and its shops can be rather hectic in the summer months with numerous vacationers. Bala was placed as having the 20th highest portion of Welsh language audio speakers in Wales by electoral department, in the United Kingdom Census 2011. According to the census, 78.5% of Bala's population can speak Welsh.