Croatia!
Flights from UK can cost around 10 euros sometimes, you can get a place for real cheap (under 100 GBP per month), beer costs about 1-1.5 GBP in bars, lunch in a restaurant can be as low as 2.5 GBP and life in general is pretty cheap (most people here live on 300-350 GBP per month). You can live on the seaside, on an island, in the mountains, in a city or combination of any of those. Literally, pick any 2 and you can find a place like that.