Where can I buy/rent helium for balloons?

I am having a party and I need a lot of balloons. I know I can buy a pack of balloons and have the store add helium to them, but is there a place I can get helium? I don’t want to keep driving back and forth to the store to get helium. Is there a place I can rent it from? I rented a generator once from Home Depot a while back, maybe there? What’s the estimated price for buying/renting helium? Thanks….........