As a native Bulgarian, I can confirm that this is how our parents taught us to treat guests ... unfortunately, there is not much left of our generation

For 65€ they could probably send a real limousine ... joking aside, this is 5x-6x what would be reasonable for this distance. Even if one wants to save themselves the hassle of using the metro for <1€ (which provides direct SOF-IC transit), taking one of the official taxis (roomy and air-conditioned) will hardly cost more than 10€.