the ACE hardware in Ft Mohave, Arizona had many different sizes of food grade plastic drums. the 55 gallon size was about 45 bucks last year.
I would not even trust a used one to be ok for potable water. I am not saying there is anything is wrong with yours but if I didn't know the seller I sure wouldn't trust what they told me. for this reason I would not pay squat for a used one unless I needed a trash can.
highdesertranger