The helium tank rental is either $19.95/day plus $.20/pound of helium used if you are using less than 1400 pounds, or $300 flat rate for a full tank (2000 pounds). If you are reserving a tank by the pound, please let us know what size and quantity of balloons you are filling so we can get a good estimate of what you will need. We gauge the tank on the way out and in and charge you for what you actually use. This is a large helium tank which will fill approximately 440 11″ helium balloons. This tank holds up to 2000psi of helium (or 220 cubic feet) and an 11″ balloon uses up to 4.2 pounds (or .5 cubic feet) of helium. A 12″ balloon uses 5.1 pounds (or .6 cubic feet), which means you can fill up to 365 12″ balloons with a full tank. We also carry balloons, curling ribbon, balloon clips, and Hi-Float.