Getting reservations at Yellowstone National Park is tricky, so unless you've managed to grab a spot one the exact right day about 6 months in advance, you'll be stuck trying to grab a "first-come, first-served" camp site. In larger campgrounds like Norris in Yellowstone, this means getting there around 6 or 7 am and hopefully getting lucky.

Indian Creek, on the other hand, still had one spot left around 11am when we got there. Looking at their booking calendar, that may have been a bit of a fluke for mid-week July (yesterday it says they booked up at 7:30 am), but it's definitely a better bet than other, more popular campgrounds.

https://www.nps.gov/yell/planyourvisit/campgrounds.htm

Decent spots, not a ton of privacy, asboluetely beautiful waterflowers, meadows and creeks surrounding the campground. There's pit toilets instead of flush, which matches the cheaper price of $15.

In theory you can have 35-foot RVs here, and the road is nice enough they should be fine, but when we were there is was almost all tents and smaller vintage or canned hams. Generators are not allowed to run at all, so that might be a deciding factor keeping the bigger rigs away.

All-in-all, a nice enough spot if you want to try out the east side of Yellowstone and/or want to get away from the larger campgrounds with more difficult bookings.