I disagree that Circus at the north end of the strip is a dump. The rooms have always been nice even if the place is filled with kids. A 10 year old would love the Adventuredome and carnival areas. I stay there pre-convention and my rooms were $22 a night. You can stay at Mandalay Bay for $120 without any discounts. I know that recently MGM Grand was available for $55. If you are worried about security and your kids I would avoid downtown - too many panhandlers and drunks. Excalibur is another kid friendly place at the south end of the strip that is priced like Circus. Unless you are taking your kid somewhere to do something special, there is not a lot for kids to do in Vegas.