If you are using a gas grill then surely you will need a propane tank. Lots of people run the grill off of their home gas line but others like to purchase the propane tanks. There are various companies that allow you to buy one tank and get it refilled at an affordable cost.
Several companies let you hire the tank and once it runs out you can return it. It entirely depends upon you; everybody comes either you can get your propane tanks delivered or go get them up yourself. If you want propane tank on rent, then you can get it from Retail Rhino LLC.
There are various companies that get your tank delivered. If you want it for a day for a party, you can set the whole thing up by calling the respective company. This gives you time to cook and set up all before you require using the grill.
Your propane tank could even be delivered before time in the day, so you can everybody comes over. There are a lot of different companies that provide propane tanks for delivery. They come in different sizes as well, that will give you sufficient propane depending how long you'll be grilling for.