I've spent 10 days in Bulgaria last summer (in July) for the first time, and I cannot recommend this country enough. It's just perfect, especially for those who like to travel off the beaten path and can't really stand the European summer heat. It's full of character, hidden gems, amazingly fun, colorful, and easy to get around... 10/10 experience and 10/10 prices as well. The food and wine — I don't even have the words!
Pictures don't do it justice, but here is a small part of the things we've seen.
We traveled by car (but we're already from the Balkans, so it was relatively close) and spent about €1,500, including some major splurging and a gorgeous but very cheap Airbnb in Bansko.
Speaking of Bansko, I know this town is famous as a winter resort, but summer in Bansko actually works perfectly. It's a mix of 24/7 entertainment, culture, and beautiful nature, and it also works as a great base for day trips.
1, 2, 20 – Rila National Park
3, 4, 5, 6, 11, 12, 13, 14 – Bansko
7, 8, 9, 10 – Pirin National Park
15, 16, 17, 18, 19 – Dobrinishte