It's going to be really hard to find some helium for rental. Many people use hydrogen because it is cheaper. Do not use hydrogen! It's explosive! Currently, there is a world shortage of helium, so try your best to call a few stores. We got ours from Bayview Balloons in Connecticut. They weren't too nice to us, so I don't recommend you to go there. Use google maps and search for helium suppliers in your area. You should get about $150 for 250 cubic feet of helium. You will only need about 100 cubic feet depending on your balloon size. The 600g ballon requires 50-100 cubic feet.