There are a couple of ways to blow up your balloons and it comes down to the quantity of balloons you need and how you want to use them.
Air inflation: The biggest advantage of air inflation is there’s no need for a tank—just take a deep breath and let your lungs do the work. For a few balloons, this is an easy option, but if you have dozens of balloons to inflate, using an air pump is something to consider.
Helium inflation: Helium will let your balloons float, which can add to the decorative quality and is always fun for kids. Helium will require a tank for inflation unless you order pre-inflated helium balloons.