When I went to Borovets last year I stayed in the Victoria and the food was fine. When I did eat out I went to Katy's and the traditional Hungarian place (forgotten the name) that is on the edge of town. If you came out of the Rila and turned left it was a large restaurant on the far side. For the two of us, with starters and an awful bottle of wine it came to £20. A word of warning, starters are the size of main courses.
In the Chinese in Pamporovo (which was delicious) 7 of us had 2 larges courses, 2 bottles of wine soft drinks and a couple of beers and a vodka, for 150 Leva, I make that about £7.00 per head!!
get your instructor to take you to chepalare cost £7.50 each four courses, mini bus all drinks and we paid for instructor as well and food was outstanding