dnd 5th – How much sealing wax is a sealing wax unit?

He says you can buy it for 5 ps but does not indicate weight. All it does is give a description "" When you press a seal ring into hot sealing wax, you leave an identification mark. "So, how could I buy a gallon of this stuff? I want to use some kind of glue to stick things together but that's the only inexpensive way to do it.