I spent 6 weeks traveling through the Western Balkans — Slovenia, Croatia (briefly), Bosnia, Montenegro, and Albania — and the costs surprised me in multiple directions.

Slovenia was not cheap. Ljubljana is a lovely small capital but food and accommodation prices are firmly Western European. Budget 70-80€/day if you want any comfort, 50€ if you're being disciplined. Skip Slovenia for budget travel unless it's a free add-on from cheap flights.

Bosnia was the revelation. Sarajevo is one of the most atmospheric cities I've visited, the food is excellent and extremely cheap (cevapi for $3, burek for $1.50), and accommodation in a good hostel ran $12-14/night. Mostar is more touristy and slightly pricier but still manageable.

Montenegro is inconsistent: the coast (Kotor, Budva) is overrun in summer and prices reflect it. The interior (Durmitor, Prokletije) is completely different — $20-30/day is doable. I strongly prefer the mountains.

Albania was the budget winner of the route. The Albanian Riviera has beaches that would cost 5x as much in Croatia. Accommodation in Himara and Dhermi in shoulder season ran $15-20 for a private room directly with the owner. Food is cheap. People are genuinely hospitable.

Overall Balkans average across the route: €38/day.