Dang that is crazy! Time to get set up with your own fill station if you use NOS and live in your area. At those prices it would pay for itself very quick!
The reason, I responded... The shop rate on Nitrous +,was 4.50 a decade ago. I co- invested ,in a local Holley distribution buyout,on a refill station.(400 bucks).I sold my side off,in parts & trade. When my partner was selling on his own,asking 5.00 a pound.(against 4.50 a pound buy in ?).