My better half is forcing me to get rid of most of my barrels that I have been saving for an upcoming business as a brew school. I originally acquired about 25 of these, and have used them for storing sacks of grain and as fermenters.
They originally housed salt water aquarium salts (my father owns an aquarium business in Florida) and have been cleaned and scrubbed with oxy clean free with hot water and a soft scrub pad.
The barrels are about 13.5 gallons, are HDPE 2 plastic, have a screw top lid and an internal snap in lid, and weight about 7 lbs empty.
For grain storage I usually use a XL Space Bag on the inside for added seal and to suck out air, but that is optional, I have friend that just pour the grain in. I would say best method depends on how long you hold grain for...
As a fermenter I just drill an airlock/blowoff hole through the lid, many of methods of doing so.
They have heavy duty handles and work great for 10 gallon batches. I use them for standard aged beers, but due to the plastic some would put into glass if fermenting for more than a month.
These are for sale at $16 each, with $14 for shipping through USPS Parcel Post. UPS and Fedex were three times higher due to the size of these (they are very light, so weight is not a factor).
I originally planned to just slap a shipping label on them, but found some boxes I can cut into cylinders to provide them a little protection.
All the barrels for sale are clean and have not been used for brewing yet, have been washed (you would probably want to wash them and sanitize them using your own methods before use).
Payment accepted is PayPal, please PM me or email me (email is faster) firstname.lastname@example.org