When I stayed in Bansko, I had the advantage of not having to stay in a Hotel. I stayed in one of the smaller family run houses. There are several of them, just ask around or try to ask around for a "staya". Alternatives are of course the bigger "commercial" hotels. I have a list but it did not feel right to me to publish them here. But if you are interested, and don't want to risk not finding a place. I can give you some adresses of the Hotels there.