Propane cost varies a lot. During Winter even the more reasonable places go up to double or more in Winter.
I had my tanks filled a couple of years ago and had a hard time getting them to work consistently. Turns out I had gotten either a propane carrier or moisture build up. The generator sputtered, stove sputtered(most noticeable) and the furnace would cut off sometimes at night. Filling up didn’t fix it..
Not sure if it is a smart or not, but this worked. I put gloves on, turned the tanks upside down and opened the flat blade screw valve on each one until the liquid stopped flowing. Then I closed the screw.