Best recommendation is to rent a helium tank from a local party supply store, or oxygen/gas/welding supply company. You can also have them individually filled at a local party supply store, call your local party supply store in advance to ensure. Store bought helium tanks are highly NOT recommended, as they are mixed with air, and air will cause the balloons to sink fast/not float. That is the same for all other balloons as well. When filled with high quality helium, the balloons can stay afloat for days. If you need further assistance on where to find helium, please message, as I am more thank happy to help locate for you.