I accidentally found myself in Yellowstone on what must have been the busiest weekend of the year. Two hours of stop and go traffic to get into the park, and no camping available that day. I resolved myself to waking up at the time the reservation office opened the next morning to try to get any cancelled reservable spot that opened up, but no luck. A nice ranger told us that Indian Creek is almost always the last campground to fill up, so we booked it over to the campground to try to get a spot. Note that Indian creek has non reservable spots, as do many campgrounds in yellowstone, which means you need to get there in the morning and get your spot before they fill up. We rolled into indian creek around 7 am and got one of the last 2 spots available in Yellowstone.
This campground is quiet, has bear boxes for your food, and has a few vault toilets available. Each site has a picnic table. Not much in the way of shade or natural barriers from your neighbors, but when you need a cheap place to stay and you don't want to drive hours to get out of the park, this place is great.