FromZwolle
I don't want to be cremated, I want to be malted.
i just purged and carbed two kegs, burned through ~150 grams co2 doing it. but i know with an aluminum tank the TW is around 25lb's it still ways 40lb's with reg. and the scale was only $25 and a second tank would be $200.....

7 lb CO2 Cylinder - Steel - Recertified | Beverage Elements
Serious value in a steel 7 lb CO2 cylinder. One of our most popular CO2 tanks, with extended capacity, slim size, and affordable price.

best price i've ever seen for a high quality tank. i can get mine filled for $25, but can't find a swap anywhere.
i have two airgas locations near me, but they will only swap