You can not just go by price. You have to check condition and for me age of the unit. But on the surface it is okay. To be honest I have a hard time giving more than a $1.00-$1.50 a gallon for a used tank because when those holiday sales roll around you can get a new tank tank for about $2.00-$2.40 a gallon. Recently a 265 went for about $1.35 a gallon at TFP. These are new tanks with a warranty. I purchased an Oceanic 210 gallon for about 1.25 a gallon used. A Oceanic which they were always considered top of the line.