In the future however, new materials may make this a feasible technology. While a vacuum is also inert and cheap, it may simply be easier to stick with good 'ol helium. I'm not sure how vacuums are presently created. A number of devices depend on vacuums, so there's no question that someone somewhere has derived a pretty good way to do it. I think the most common way is with simple fans.
Fans simply blow the air out of a contained volume and the air density decreases.
However, this method cannot possibly create a perfect vacuum. The decrease in density must drop off asymptotically without every reaching zero. This is a simply physics experiment that I learned about a long time ago. If you submerge a glass in a bowl of water, turn it upside down, and pull it up out of the water, it will come up completely filled with water even though it is above the waterline. The reason for this is simple.