All the same, Rila in the village of Kranevo is the most economical hotel. And pretty close to the sea. The room has 2 beds, a table, ottomans, clean bedding, new towels.
I went with a child of 2.8 years for 10 days. Now I understand that you need to be very careful with the choice of hotel. And of course, since I am, don't trust the agency 100%.
The last time I was in Bulgaria was in 2003 at the Rila 2* hotel. Two weeks were an unforgettable vacation (The whole trip was paid for by work; the group included both young people and older people, as well as children of the year 3-4).