I highly recommend the Treasure State Hostel on Main Street! I had never stayed in a hostel before and this one checked all the boxes: clean, quiet, well-heated (it was Thanksgiving week) and plenty of hot water for showers. Except for a couple of oldsters like me, everyone there seemed to be in their 20s and were very respectful of other people and the space. The managers were also very good. I rented a private room, and the price and location were unbeatable. I'll be staying there whenever I return to Bozeman!