“All my life I thought air was free…until I bought a bag of chips”

“All my life I thought air was free..until I bought a bag of chips” is a jocular line that has been printed on many posters. “I remember when buying a bag of chips was normal…now a bag of chips is 80% air..I thought air was free” was cited on Twitter on July 26, 2010.
 
“All my life I thought air was free, until I bought a bag of chips” was cited on Twitter on October 19, 2012.
 
   
Twitter
photographer
‏@Asstigram
I remember when buying a bag of chips was normal…now a bag of chips is 80% air..I thought air was free =/ must be hookah
1:28 AM - 26 Jul 2010
 
Twitter
keenon
‏@Orielus
Buying a bag of chips that has mostly air in it. AIR IS FREE. stop charging me for it -.- #ThatIrritatesMe
6:15 PM - 27 Mar 2012
 
Twitter
Sarcasm
‏@TheFunnyTeens
All my life I thought air was free, until I bought a bag of chips.
9:05 AM - 19 Oct 2012
 
Twitter
Men’s Humor
‏@MensHumor
All my life I thought air was free…until I bought a bag of chips.
8:40 PM - 23 Oct 2012
   
Mental Floss 
August 1, 2013 - 9:30am
Why Are Potato Chip Bags Always Half-Empty?
Roma Panganiban
(...)
When products are stacked atop one another, crammed into tight spaces, or simply jostled around in the back of a delivery truck, slack fill serves as an air cushion that prevents potato chips from becoming potato crumbs.
 
That’s not just any ordinary air puffing up potato chip bags, either: It’s nitrogen. Oxygen can cause the potatoes to spoil and the oil to go rancid, and the humidity found in ambient air makes the chips go soggy. Instead, packages are filled with nitrogen gas to help the snacks stay fresh, which a trained panel of tasters confirmed in a 1994 food science study.
(...)
So while some extra space in a bag can help keep potato chips fresh and intact, any more than necessary might be the company trying to pull a fast one over us.