My son LOVED going there last year. It was definitely not cheap. I seem to remember everything costing around $50. I believe the chassis he chose was around $25, but he added stuff on. He really wanted a car with working headlights.
If we ever went back, I would bring my own batteries (they were not included). I believe you need one 9-Volt for the remote, and two AA's for the car. DS is alseep, but I can ask him in the morning. After spending all that time picking out everything for his car, and then making it, we weren't going to tell him we couldn't buy batteries. He wanted to start driving it right then and there. And I don't think the batteries were cheap....I remember DH doing a double take at the employee after he told us how much they cost.
Like the previous poster, we went in the afternoon. We had visited the evening before and it was really crowded at night. Although they have since remodeled and made it bigger. Hope you guys have a great time!