Bansko is a small mountain town with the biggest walking distance between the two ends of town being 30min hence there is no public bus in Bansko. In winter there are private ski shuttles going to and from the hotels to the Gondola Ski Lift station. They are ONLY for hotel residents.
If you need to go to neighboring Razlog for a Lidl run, there are buses every hour to Razlog from Bansko main bus station. If you want to take the train to Dobriniste to visit one of the hot springs there, hike or ski at Bezbog or eat at the Mehanas, you can hop on the narrow gauge trailway which runs 5 times a day and takes about 15min to arrive. For schedule of Bansko to Dobriniste train, check here: https://visit-bansko.bg/bg/полезно/гара-–-разписание
There are no public buses running to the neighboring village of Banya where a lot of the hot springs are located. Members often car pool or share a taxi when going for a dip at night. All these towns around Bansko are just a short bicycle ride away which is the preferred method of transportation in summer - 30-45min depending on your speed and the route you choose.
Captured from OpenStreetMap.org
Bansko Bus Titmetable, Bansko Bus Station