Our day tour was $10 and it started out in the visiting room in the penitentiary. The guide gave us some history of each stop and along the way through the grounds, she also pointed out the murals painted by the prisoners. The entire tour was about 1hr-1.5 hrs and she kept us moving to several spots inside and outside. We ended at the small museum near the visitors center. Hearing all the incredible stories made the tour very interesting...some stories were absolutely shocking! I never realized how bad it really was there until the government deemed the penitentiary as "cruel and unusual punishment". I wanted to see so much more of the building but it is very vast. We did not go into the famous "Sugar Shack" because that area is reserved for the overnight tours.
I have heard of people bringing small children to this and there was one on our tour as well. I have a feeling the guide edited down her stories to accommodate the child, but I don't think it is the best idea to take a child on a tour of America's most violent and haunted prison.
I do recommend reading a bit about the history if you have never been because it gives you an understanding of what you are about to see. They do allow photography and parking is free in front of the building. Also leave a little bit of time to explore the Grave Creek burial mound across the street, gives you an amazing view of the pen. We traveled about 10-15 minutes into Wheeling, WV and found some great shops and good cafes as well.