Bulgaria's capital — cheapest EU city for nomads. Strong outsourcing/IT scene, mountains within day-trip range.
From Wikipedia
Sofia is the capital and largest city of Bulgaria. It is situated in the Sofia Valley at the foot of the Vitosha mountain, in the western part of the country. The city is built west of the Iskar river and has many mineral springs, such as the Sofia Central Mineral Baths. It has a humid continental climate.