Tall tank will fill 600 balloons when full. We measure it when you take it and then when you return and charge you for what you have used. Helium prices vary, about $12/100psi. A 100 psi does about 25-35 balloons depending on size.
15 inch mirror ball hangs from a 48 inch bar with lights on either end. Motor on the bar turns the ball. Hang the bar from your ceiling.