You can also skip out on the helium tank to save even more. After all, blowing them up yourself is like half the fun of having balloons in the first place.
And especially now that internet shopping is a thing, you can easily buy the bulk bags that balloon manufacturers sell to vendors. That's usually how I buy my balloons. Get a ton of balloons for about 65%-70% the normal cost.
Balloon drawer? Try a stack of 3 jumbo Rubbermaid balloon storage containers.