Firstly it would be difficult finding an apartment to rent, especially for a foreigner. Depending on location rents for 2 bedroom apartments (50-65m2) are about 700-900 EUR per month plus expenses (heating, cleaning, garbage disposal), parking if you have a car etc. That could mean around 1500 EUR per month. Since 2014 rents have gone up 10% each year. The centre of Ljubljana is full of Airbnb rentals, hence the high prices. Food and drink is relatively cheap compared to northern and western parts of Europe. For an adult male the cost for food and drink would be about 120 EUR per month. To travel around Slovenia frequently and comfortably you need a car, because public transport is slow and quite expensive. Based on that I'd say 50 000 EUR for a family of 3 would last 2 years max.