To purchase a vacuum cleaner bag, begin by deciding what brand you will need. Next, determine the style of the bag. This can be found on your old vacuum cleaner bag. A reorder number or bag type should be written on the outside of the vacuum cleaner bag. It is important to keep in mind that if you buy bags in larger quantities you may be able to save on shipping costs when purchasing them online. It might be a good idea to check with your friends to see if they need to order bags, too.