Don't know about food grade containers but I know of a fair supply of tanks to use for storing water and they usually have several on hand at the stores. Check them out here: http://www.tractorsupply.com/webapp/wcs ... perPage=20

If they don't have what you want in stock, they can get them ordered and delivered to the store rather quickly and there isn't anything special about getting them. Pay the price, get the tank, go on your way, no worries.

Thats a real good price but you know they were probably manufactured in Cheena. A surplus store gets $30 for a beater type military plastic 5 gallon gas can but those things are tough and can take a lot of hard abuse. I bought 2- 5 gallon water storage cans at Wallyworld and within a year they disintigrated. They were the thin skinned el cheapos and would not take much abuse.
At this moment in history large agricultural ranch type water storage tanks are being bought up as soon as they are produced. The grange is out of them and you must put your name on a waiting list to purchase one. Don't know why the demand is so high. I wanted to get a medium sized 1500 gallon model so I could install it myself. A 3000 gallon unit will just barely fit in a full sized pick up truck bed and you need 3 people to wrestle it into place. I did not put my name on the waiting list for fear of the county ascessor seeing it there.

I rode to chinamart with LG last night and wandered around. They actually had 6 gallon food grade containers that looked a lot like military gas cans for $10. They were hard plastic that seemed very hardy and in a shape that would not take up much room and slide into any slim area. I did not buy any but I may have to go back and invest. These would slip easily behind a seat in a pickup and they had a good balance and heavily built handle for easier carrying.