One of my housemates last winter was our "chauffeur" at Big Sky. He would drop everyone off, then go park. We would take his stuff in with us. Since we were early birds who arrived well before the lifts were running, he either walked from the parking lot or hopped the tram shuttle.
Did much the same at Bridger. There were four of us staying at a motel near the airport for those ski days after the gathering was over.
Big Sky provide free parking but you need to take a shuttle from the parking lot to the base area. The shuttles run every 5 to 10 minutes usually but can get crowded heading back at the end of the day. Fortunately, you can ski back to the free parking at the end of the day & if you already have your ticket you can jump on the very slow Explorer chair which isn't too far from the parking. There is a small lot at the base area you can pay to park in but it fills fast on weekends. I don't know what the costs are anymore but it used to run $20 for a day. Lastly, Big Sky runs a free bus system during the winter. Many people use that to get from their condos to the base area.