Balloon Rental Best And Cheapest Place To Rent A Helium Tank In San Diego Area?

Best and cheapest place to rent a helium tank in San Diego area? - balloon rental

OK, so I have to be a tank of helium in a position to fly at least 100 balloons. I know that part of the city helium tank rental, but who are they? and would also be cheaper to buy or to rent a tank, because her class and I am sophomore and balloons, we have twice a year at most?

ps. preferably in the region of El Cajon, but if San Diego was also a fine